US7823212B2 - Securely aggregating content on a storage device - Google Patents

Abstract

An aggregation system aggregates contents recorded on a plurality of recording mediums and recording them onto another recording medium while protecting the copyrights of the contents is provided. The aggregation system includes an aggregation apparatus and a reproduction apparatus. The aggregation apparatus obtains a main content from an optical disc, obtains a sub content from a memory card, and aggregates the obtained main content and sub content and records them onto a portable medium. The reproduction apparatus obtains the main content from the optical disc, obtains reproduction control information for controlling reproduction of the main content, and reproduces the main content recorded on the optical disc based on the reproduction control information.

Description

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a technique for recording a content which is recorded on a recording medium onto another recording medium, and particularly to an aggregation system for aggregating contents which are recorded on a plurality of recording mediums and recording them onto a single recording medium.

2. Background Art

With the advance of digital signal compression technology and recording technology, it has become common in recent years to sell contents which are digital copyrighted works, such as music, video and programs, recorded on recording mediums such as high-capacity optical discs like digital versatile discs (DVDs). It is possible to copy such digital contents recorded on the recording mediums to other recording mediums like hard disks and the like without deterioration in quality. Therefore, the copyrights of such contents are in danger of being infringed by unauthorized uses and copying thereof, and thus the solution of this problem has been demanded.

As one of the conventional methods for preventing unauthorized uses and copying by third parties, there is the Content Protection for Recordable Media (CPRM) standard, that is, a well-known scheme for preventing unauthorized copying of contents recorded on recording mediums (See, for example, “p. 7 of Matsushita Technical Journal, Vol. 48, No. 2 (April, 2002), issued on Apr. 18, 2002 by Matsushita Electric Industrial Co., Ltd.). This scheme will be briefly explained below.

First, on a recording medium manufactured in compliance with the CPRM standard, a medium ID that is unique to the recording medium is recorded when it is manufactured. This medium ID is the information which can be read but cannot be rewritten nor deleted. When a recording device manufactured in compliance with this standard records a content on a recording medium, it generates a content key by a predetermined method using the medium ID of the recording medium, and records, on the recording medium, the content encrypted by a predetermined method using the content key. Under this scheme, an encrypted content recorded on a recording medium A can be copied to another recording medium B. However, the medium ID of the destination recording medium B is different from the medium ID of the source recording medium A. Therefore, a reproduction device manufactured in compliance with this standard cannot obtain a content key for decrypting the encrypted content which has been recorded on the source recording medium A, even if it generates a content key by a predetermined method by reading the medium ID of the destination recording medium B. As a result, the content which is copied onto the recording medium B cannot be decrypted, and thus unauthorized copying can be prevented.

On the other hand, with the recent widespread of the Internet, various types of contents such as music and video have been obtained via the Internet. It is supposed, for example, that video and audio data are recorded on a DVD and a user who purchased the DVD can not only reproduce and view (and listen to) the video and audio data but also replace the audio data recorded on the DVD with another audio data obtained via the Internet and recorded on another recording medium. In this case, the wider the variety of replaceable audio data is, the more the variety of uses of the content recorded on the DVD increases, which enhances the commercial value of the content more and more.

Under these circumstances, it is expected to distribute contents not only via the above-mentioned recording mediums like DVDs but also in other manners for increasing the commercial value of the contents. For example, it may be possible for a user to obtain, via the Internet, a sub content which is to be used in association with a content recorded on a recording medium like a DVD, record the sub content on another recording medium (a hard disk, a high-capacity memory card or the like, for example), and reproduce the content by associating it with the sub content recorded on another recording medium.

It is also expected, in the above-mentioned content distribution manner, to distribute, as a sub content, the modification or addition data for the content recorded on a DVD and reproduce the content recorded on the DVD by associating it with the sub content so as to reproduce the updated content.

In this case, since the content and the sub content to be used in association with the content are recorded on separate recording mediums, a user has to carry a plurality of recording mediums to use these contents in various places. Therefore, it is anticipated, in the above-mentioned content distribution manner, that the use of these contents which are aggregated and recorded on another recording medium will be demanded for the sake of enhanced convenience of portability, for example. This type of usage results in actual copying of the content and the sub content if these contents recorded on separate recording mediums are just aggregated and recorded on another recording medium, because the content and the sub content can be reproduced from both of the source recording mediums and the destination recording medium on which the aggregated contents are recorded. Therefore, some measures must be taken in order to protect the copyrights of the contents.

However, the conventional technology like the CPRM standard is a scheme for preventing unauthorized copying of the contents recorded on a single recording medium in order to protect the copyrights of the contents, and there is no method for aggregating contents recorded on a plurality of recording mediums and recording them on another recording medium in order to enhance users' convenience, while at the same time protecting the copyrights of the contents.

The object of the present invention, in view of the above problem, is to provide an aggregation apparatus for aggregating contents recorded on a plurality of recording mediums and recording them on another recording medium while protecting the copyrights of the contents, a reproduction apparatus for reproducing the aggregated contents while protecting the copyrights of the contents, and an aggregation system for aggregating the contents while protecting the copyrights thereof or for reproducing the aggregated contents while protecting the copyrights thereof.

It should be noted that the above-mentioned aggregation or reproduction of contents under the protection of the copyrights thereof means the aggregation or reproduction of the contents based on the consent of the copyright owners to aggregate or reproduce the contents.

SUMMARY OF THE INVENTION

The aggregation system according to the present invention is an aggregation system comprising an aggregation apparatus, a first reproduction apparatus and a second reproduction apparatus, wherein the aggregation apparatus includes: a first obtainment unit operable to obtain a main content from a first recording medium; a second obtainment unit operable to obtain a sub content; and a recording unit operable to aggregate the main content and the sub content and record the aggregated contents onto a second recording medium, the first reproduction apparatus includes: a third obtainment unit operable to obtain the main content from the first recording medium; a fourth obtainment unit operable to obtain reproduction control information for controlling reproduction of the main content; and a reproduction unit operable to reproduce the main content recorded on the first recording medium, based on the reproduction control information, and the second reproduction apparatus reproduces the main content and the sub content which are recorded on the second recording medium.

The aggregation apparatus according to the present invention is an aggregation apparatus for aggregating a main content recorded on a first recording medium and a sub content and recording the aggregated contents onto a second recording medium, wherein reproduction control information indicating whether or not reproduction of the main content is permitted is recorded on the first recording medium, and the aggregation apparatus comprises: a first obtainment unit operable to obtain the main content from the first recording medium; a second obtainment unit operable to obtain the sub content; a third obtainment unit operable to obtain the reproduction control information from the first recording medium; a judgment unit operable to judge whether or not the reproduction control information is information indicating that reproduction of the main content is permitted; a recording unit operable to aggregate the main content and the sub content and record the aggregated contents onto the second recording medium, when the judgment unit judges that the reproduction control information is the information indicating that reproduction of the main content is permitted; and a changing unit operable to change the reproduction control information recorded on the first recording medium so that the reproduction control information indicates that reproduction of the main content is not permitted, in the case where the main content and the sub content are recorded onto the second recording medium by the recording unit.

The reproduction apparatus according to the present invention is a reproduction apparatus for reproducing a main content recorded on a recording medium, wherein reproduction control information indicating whether or not reproduction of the main content is permitted is recorded on the recording medium, and the reproduction apparatus comprises: a first obtainment unit operable to obtain the main content from the recording medium; a second obtainment unit operable to obtain the reproduction control information from the recording medium; a judgment unit operable to judge whether or not the reproduction control information is information indicating that reproduction of the main content is permitted; and a reproduction unit operable to reproduce the main content recorded on the recording medium, when the judgment unit judges that the reproduction control information is the information indicating that reproduction of the main content is permitted.

The reproduction apparatus according to the present invention is a reproduction apparatus for reproducing an encrypted main content and a sub content which are recorded on a second recording medium after the encrypted main content recorded on a first recording medium and the sub content are aggregated and recorded onto the second recording medium, wherein a decryption key for decrypting the encrypted main content is recorded on the first recording medium, and the reproduction apparatus comprises: a first obtainment unit operable to obtain the encrypted main content from the second recording medium; a second obtainment unit operable to obtain the decryption key from the first recording medium; and a decryption unit operable to decrypt the encrypted main content using the decryption key.

The aggregation system according to the present invention is an aggregation system comprising an aggregation apparatus and a reproduction apparatus, wherein the aggregation apparatus includes: a first obtainment unit operable to obtain a main content; a second obtainment unit operable to obtain a sub content; a third obtainment unit operable to obtain aggregation judgment information indicating whether or not aggregation of the main content and the sub content and recording of the aggregated contents onto a recording medium are permitted; a judgment unit operable to judge whether or not the aggregation judgment information is information indicating that aggregation of the main content and the sub content and recording of the aggregated contents onto the recording medium are permitted; and a recording unit operable to aggregate the main content and the sub content and record the aggregated contents onto the recording medium, when the judgment unit judges that the aggregation judgment information is the information indicating that aggregation and recording onto the recoding medium are permitted, and the reproduction apparatus reproduces the main content and the sub content which are recorded on the recording medium.

The aggregation apparatus according to the present invention is an aggregation apparatus for aggregating a main content and a sub content and recording the aggregated contents onto a first recording medium, comprising: a first obtainment unit operable to obtain the main content; a second obtainment unit operable to obtain the sub content; a third obtainment unit operable to obtain aggregation judgment information indicating whether or not aggregation of the main content and the sub content and recording of the aggregated contents onto the first recording medium are permitted; a judgment unit operable to judge whether or not the aggregation judgment information is information indicating that aggregation of the main content and the sub content and recording of the aggregated contents onto the first recording medium are permitted; and a recording unit operable to aggregate the main content and the sub content and record the aggregated contents onto the first recording medium, when the judgment unit judges that the aggregation judgment information is the information indicating that aggregation and recording onto the first recording medium are permitted.

The aggregation system according to the present invention is an aggregation system comprising an aggregation apparatus, and a reproduction apparatus, wherein the aggregation apparatus includes: a first obtainment unit operable to obtain a main content; a second obtainment unit operable to obtain a sub content; and a recording unit operable to aggregate the main content and the sub content and record the aggregated contents onto a recording medium, and the reproduction apparatus includes: a judgment unit operable to judge whether or not a situation of reproduction of the main content and the sub content satisfies a predetermined condition indicating that reproduction of the main content and the sub content is permitted, and a reproduction unit operable to reproduce the main content and the sub content which are recorded on the recording medium, when the judgment unit judges that the situation satisfies the predetermined condition.

The reproduction apparatus according to the present invention is a reproduction apparatus for reproducing a main content and a sub content which are aggregated and recorded onto a recording medium, comprising: a judgment unit operable to judge whether or not a situation of reproduction of the main content and the sub content satisfies a predetermined condition indicating that reproduction of the main content and the sub content is permitted; and a reproduction unit operable to reproduce the main content and the sub content which are recorded on the recording medium, when the judgment unit judges that the situation satisfies the predetermined condition.

As described above, the aggregation system, the aggregation apparatus and the reproduction apparatus of the present invention allow aggregation of contents recorded on a plurality of recording mediums and their recording on another recording medium while protecting the copyrights of the contents, or allow reproduction of the aggregated contents while protecting the copyrights thereof.

In addition, the present invention can be realized as a method including the steps executed by the characteristic units included in the aggregation apparatus or the reproduction apparatus of the present invention, or as a program including these steps. The program can also be distributed via a recording medium such as a CD-ROM or a transmission medium such as a communication network.

As further information about technical background to this application, Japanese Patent Application No. 2003-116836 filed on Apr. 22, 2003 is incorporated herein by reference.

BRIEF DESCRIPTION OF DRAWINGS

These and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings that illustrate a specific embodiment of the invention. In the Drawings:

FIG. 1 is a diagram showing a configuration of anaggregation system1 in a first embodiment;

FIG. 2 is a diagram showing a structure of anoptical disc11 in the first embodiment;

FIG. 3 is a diagram showing a structure of anaggregation apparatus16 in the first embodiment;

FIG. 4 is a diagram showing a structure of areproduction apparatus17 in the first embodiment;

FIG. 5 is a flowchart showing processing of theaggregation apparatus16 in the first embodiment;

FIG. 6 is a flowchart showing processing of thereproduction apparatus17 in the first embodiment;

FIG. 7 is a diagram showing a structure of anoptical disc11ain the first embodiment;

FIG. 8 is a diagram showing a structure of anoptical disc11bin the first embodiment;

FIG. 9 is a diagram showing a structure of anoptical disc11cin the first embodiment;

FIG. 10 is a diagram showing a configuration of anaggregation system2 in a second embodiment;

FIG. 11 is a diagram showing a structure of anaggregation apparatus26 in the second embodiment;

FIG. 12 is a diagram showing a structure of areproduction apparatus27 in the second embodiment;

FIG. 13 is a flowchart showing processing of theaggregation apparatus26 in the second embodiment;

FIG. 14 is a flowchart showing processing of thereproduction apparatus27 in the second embodiment;

FIG. 15 is a diagram showing structures ofoptical discs21a,21band21cand decryptionkey storage mediums221a,221band221c;

FIG. 16 is an illustration of processing for recording collectively, on a decryptionkey storage medium221d, decryption keys a, b and c which are respectively recorded on the decryptionkey storage mediums221a,221band221c;

FIG. 17 is a diagram showing a structure of theoptical disc21ain the second embodiment;

FIG. 18 is a diagram showing structures of theoptical disc21 and aportable medium23 in the second embodiment;

FIG. 19 is a diagram showing an example of a decryption key list managed by aserver24 in the second embodiment;

FIG. 20 is a diagram showing an example of a decryption key list managed by theserver24 in the second embodiment;

FIG. 21 is a diagram showing a configuration of anaggregation system3 in a third embodiment;

FIG. 22 is a diagram showing a structure of anoptical disc31 in the third embodiment;

FIG. 23 is a diagram showing an example of medium IDs and aggregation judgment information in the third embodiment;

FIG. 24 is a diagram showing a structure of anaggregation apparatus36 in the third embodiment;

FIG. 25 is a diagram showing a structure of areproduction apparatus37 in the third embodiment;

FIG. 26 is a flowchart showing processing of theaggregation apparatus36 in the third embodiment;

FIG. 27 is a flowchart showing processing of thereproduction apparatus37 in the third embodiment;

FIG. 28 is diagram showing an example of medium IDs, sub content IDs and aggregation judgment information in the third embodiment;

FIG. 29 is a diagram showing an example of medium IDs, information indicating whether or not to bill a user and aggregation judgment information in the third embodiment;

FIG. 30 is a diagram showing an example of medium IDs, information indicating whether or not to bill a user and aggregation judgment information in the third embodiment;

FIG. 31 is a diagram showing an example of medium IDs, information indicating the number of user's aggregations and aggregation judgment information in the third embodiment;

FIG. 32 is a diagram showing another structure of theoptical disc31 in the third embodiment;

FIG. 33 is a diagram showing a configuration of anaggregation system4 in a fourth embodiment;

FIG. 34 is a diagram showing a structure of a portable medium43 in the fourth embodiment;

FIG. 35 is a diagram showing a structure of anaggregation apparatus46 in the fourth embodiment;

FIG. 36 is a diagram showing a structure of areproduction apparatus47 in the fourth embodiment;

FIG. 37 is a flowchart showing processing of theaggregation apparatus46 in the fourth embodiment; and

FIG. 38 is a flowchart showing processing of thereproduction apparatus47 in the fourth embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The best mode for carrying out the present invention will be explained below with reference to the drawings.

First Embodiment

First, anaggregation system1 in the first embodiment of the present invention will be explained below with reference toFIG. 1 toFIG. 6.

When an aggregation apparatus aggregates contents recorded on a plurality of recording mediums and records them onto another recording medium, thisaggregation system1 does not reproduce, after the aggregation, the content which has been recorded on the recording medium before the aggregation.

Overview of Aggregation System

First, the overview of theaggregation system1 in the first embodiment will be provided with reference toFIG. 1.FIG. 1 is a block diagram showing the configuration of theaggregation system1 in the first embodiment.

InFIG. 1, a content such as a movie is recorded, as a main content, on anoptical disc11, a sub content such as audio data to be used in association with the main content recorded on theoptical disc11 can be recorded on amemory card12, and aportable medium13 is a portable medium such as a DVD-RAM on which information can be recorded. Note that the portable medium13 may be a removable hard disk drive (HDD), or may be replaced with a recording medium such as a nonremovable HDD.

A content provider distributes the main content to a user via a distribution means such as a sale of the main content recorded on theoptical disc11, and distributes the sub content to be used in association with the main content to the user from aserver14 via theInternet18.

On the other hand, the user obtains the sub content from theserver14 via theInternet18 using a subcontent obtainment apparatus15, and records it on thememory card12. Then, using areproduction apparatus17, the user reproduces the main content recorded on theoptical disc11 by associating it with the sub content recorded on thememory card12, and views it.

In order to enhance convenience of portability, the user can also aggregate both the main content recorded on theoptical disc11 and the sub content recorded on thememory card12 and record them onto theportable medium13, using anaggregation apparatus16. The user can also reproduce and view the main content and the sub content which are recorded on theportable medium13, using thereproduction apparatus17. Note that after aggregating the main content and the sub content and recording them onto theportable medium13, theaggregation apparatus16 takes a process so that the main content recorded on theoptical disc11 cannot be reproduced.

In other words, thisaggregation system1 is a system for protecting copyrights of contents by not reproducing a main content which has been recorded on a recording medium before aggregation, after a user aggregates the contents recorded on a plurality of recording mediums and records them onto another recording medium.

The overview of theaggregation system1 in the first embodiment has been provided, and the detailed explanation of theaggregation system1 will follow.

Configuration ofAggregation System1

As shown inFIG. 1, theaggregation system1 includes theoptical disc11, thememory card12, theportable medium13, theserver14, the subcontent obtainment apparatus15, theaggregation apparatus16 and thereproduction apparatus17. Theserver14 and the subcontent obtainment apparatus15 are connected to each other via theInternet18.

Structure ofOptical Disc11

Theoptical disc11 is a recording medium such as a DVD-RAM on which information can be recorded.FIG. 2 shows the structure of theoptical disc11. As shown inFIG. 2, on theoptical disc11, a main content and reproduction judgment information (flag) indicating whether reproduction of the main content is permitted or not are recorded. It is assumed here that the default value of the reproduction judgment information is a value indicating that the reproduction is permitted, and it is “1” in the first embodiment.

Structure ofMemory Card12

Thememory card12 is a recording medium such as an SD card on which information can be recorded. On thememory card12, a sub content to be used in association with the main content is recorded by the subcontent obtainment apparatus15.

Structure ofPortable Medium13

Theportable medium13 is a portable medium such as a DVD-RAM on which information can be recorded. The main content recorded on theoptical disc11 and the sub content recorded on thememory card12 are aggregated and recorded onto the portable medium13 by theaggregation apparatus16. Note that the portable medium13 may be a removable HDD, or may be replaced with a recording medium such as a nonremovable HDD. In short, the portable medium13 or the recording medium that replaces the portable medium13 must be a recording medium on which aggregated main content and sub content are recorded.

Structure ofServer14

Theserver14 holds the sub content to be used in association with the main content recorded on theoptical disc11, and provides the subcontent obtainment apparatus15 with the sub content.

Structure of SubContent Obtainment Apparatus15

The subcontent obtainment apparatus15 obtains the sub content from theserver14 via theInternet18, and records it on thememory card12.

Structure ofAggregation Apparatus16

FIG. 3 shows the structure of theaggregation apparatus16. As shown inFIG. 3, theaggregation apparatus16 includes afirst access unit161, asecond access unit162, acontrol unit163, athird access unit164, aninput unit165 and adisplay unit166.

(1)First Access Unit161

Thefirst access unit161 reads the main content and the reproduction judgment information from theoptical disc11 according to the instruction of thecontrol unit163. Thefirst access unit161 also rewrites the reproduction judgment information on theoptical disc11 according to the instruction of thecontrol unit163.

(2)Second Access Unit162

Thesecond access unit162 reads the sub content from thememory card12 according to the instruction of thecontrol unit163.

(3)Control Unit163

Thecontrol unit163 reads the main content and the reproduction judgment information from theoptical disc11 via thefirst access unit161, and reads the sub content from thememory card12 via thesecond access unit162.

When the value of the reproduction judgment information read from theoptical disc11 is 1, thecontrol unit163 writes the main content and the sub content onto theportable medium13 via thethird access unit164. Then, thecontrol unit163 rewrites, via thefirst access unit161, the value of the reproduction judgment information on theoptical disc11 from 1 to another value than 1, for example, 0.

(4)Third Access Unit164

Thethird access unit164 writes the main content and the sub content onto the portable medium13 according to the instruction of thecontrol unit163.

(5)Input Unit165

Theinput unit165 accepts an input of an aggregation instruction from a user.

Then, upon receipt of the input of the aggregation instruction from the user, theinput unit165 causes thecontrol unit163 to operate.

(6)Display Unit166

After completing the processing of thecontrol unit163, thedisplay unit166 notifies the user of the end of the processing by displaying it.

Structure ofReproduction Apparatus17

FIG. 4 shows the structure of thereproduction apparatus17. As shown inFIG. 4, thereproduction apparatus17 includes afirst access unit1701, asecond access unit1702, athird access unit1703, acontrol unit1704, areproduction unit1705 and aninput unit1706.

(1)First Access Unit1701

Thefirst access unit1701 reads the main content and the reproduction judgment information from theoptical disc11 according to the instruction of thecontrol unit1704.

(2)Second Access Unit1702

Thesecond access unit1702 reads the sub content from thememory card12 according to the instruction of thecontrol unit1704.

(3)Third Access Unit1703

Thethird access unit1703 reads the main content and the sub content from the portable medium13 according to the instruction of thecontrol unit1704.

(4)Control Unit1704

Thecontrol unit1704 performs either the following processing (i) or (ii) according to the instruction of theinput unit1706.

(i) To cause thereproduction unit1705 to reproduce the main content recorded on theoptical disc11 and the sub content recorded on thememory card12 by associating them with each other.

Thecontrol unit1704 reads the main content and the reproduction judgment information from theoptical disc11 via thefirst access unit1701, and reads the sub content from thememory card12 via thesecond access unit1702. When the value of the reproduction judgment information read from theoptical disc11 is 1, thecontrol unit1704 causes thereproduction unit1705 to reproduce the main content and the sub content by associating them with each other and output them to the outside. Note that when the value of the reproduction judgment information is not 1, thecontrol unit1704 does not cause thereproduction unit1705 to reproduce the main content and the sub content.

It is assumed in the first embodiment that the main content is digital data composed of audio data and video data and the sub content is digital data composed of audio data, for example. In this case, thecontrol unit1704 causes thereproduction unit1705 to replace the audio data in the main content with the audio data in the sub content, so that the main content recorded on theoptical disc11 and the sub content recorded on thememory card12 are reproduced in association with each other.

(ii) To cause thereproduction unit1705 to reproduce the main content and the sub content which are recorded on the portable medium13 by associating them with each other.

Thecontrol unit1704 reads the main content and the sub content from theportable medium13 via thethird access unit1703. Then, thecontrol unit1704 causes thereproduction unit1705 to reproduce the main content and the sub content by associating them with each other and output them to the outside.

(5)Reproduction Unit1705

Thereproduction unit1705 reproduces the main content and the sub content by associating them with each other under the control of thecontrol unit1704, and outputs the reproduced data to amonitor171 and aspeaker172 which are connected to thereproduction unit1705. Themonitor171 and thespeaker172 output the data reproduced by thereproduction unit1705 to the outside.

(6)Input Unit1706

Theinput unit1706 accepts an instruction to reproduce theoptical disc11 or an instruction to reproduce the portable medium13 from the user.

Upon receipt of the instruction to reproduce theoptical disc11, theinput unit1706 causes thecontrol unit1704 to operate so that the main content recorded on theoptical disc11 and the sub content recorded on thememory card12 are reproduced in association with each other.

On the other hand, upon receipt of the instruction to reproduce theportable medium13, theinput unit1706 causes thecontrol unit1704 to operate so that the main content and the sub content which are recorded on the portable medium13 are reproduced in association with each other.

Operation ofAggregation System1

The configuration of theaggregation system1 has been explained, and the detailed explanation of the operations of theaggregation apparatus16 and thereproduction apparatus17, as the operation of theaggregation system1, will follow.

Operation ofAggregation Apparatus16

The operation of theaggregation apparatus16 will be explained with reference to the flowchart as shown inFIG. 5.

When theinput unit165 receives the input of the aggregation instruction from the user, theaggregation apparatus16 performs the following processing.

First, thecontrol unit163 reads the main content and the reproduction judgment information from theoptical disc11 via thefirst access unit161, and reads the sub content from thememory card12 via the second access unit162 (Step S101).

Next, thecontrol unit163 checks whether the value of the reproduction judgment information read from theoptical disc11 is 1 or not (Step S102), and when the value of the reproduction judgment information is not 1 but 0, for example (No in Step S102), the operation of theaggregation apparatus16 ends.

On the other hand, when the value of the reproduction judgment information is 1 (Yes in Step S102), thecontrol unit163 writes the main content and the sub content onto theportable medium13 via the third access unit164 (Step S103).

Then, thecontrol unit163 rewrites the value of the reproduction judgment information on theoptical disc11 to another value than 1, for example, 0, via the first access unit161 (Step S104).

Next, thedisplay unit166 displays that writing of the main content and the sub content onto theportable medium13 has been completed (Step S105). Then, the operation of theaggregation apparatus16 ends.

Operation ofReproduction Apparatus17

The operation of thereproduction apparatus17 will be explained with reference to the flowchart as shown inFIG. 6.

When theinput unit1706 receives the instruction to reproduce theoptical disc11 or the instruction to reproduce the portable medium13 from the user, thereproduction apparatus17 performs the following operation.

First, theinput unit1706 checks whether the received reproduction instruction is the instruction to reproduce theoptical disc11 or the instruction to reproduce the portable medium13 (Step S151). The processing goes to Step S152 in the case of the instruction, to reproduce theoptical disc11, whereas the processing goes to Step S155 in the case of the instruction to reproduce theportable medium13.

To be more specific, in a case where the reproduction instruction received by theinput unit1706 is the instruction to reproduce the optical disc11 (No in Step S151), thecontrol unit1704 reads the main content and the reproduction judgment information from theoptical disc11 via thefirst access unit1701, and reads the sub content from thememory card12 via the second access unit1702 (Step S152).

Next, thecontrol unit1704 checks whether the value of the reproduction judgment information read from theoptical disc11 is 1 or not (Step S153). When the value of the reproduction judgment information is not 1 but 0, for example (No in Step S153), the operation of thereproduction apparatus17 ends.

When the value of the reproduction judgment information is 1 (Yes in Step S153), thecontrol unit1704 causes thereproduction unit1705 to reproduce the main content read from theoptical disc11 and the sub content read from thememory card12 by associating them with each other (Step S154). The reproduced data is outputted to the outside via themonitor171 and thespeaker172. As such, the operation of thereproduction apparatus17 ends.

On the other hand, in a case where the reproduction instruction received by theinput unit1706 is the instruction to reproduce the portable medium13 (Yes in Step S151), thecontrol unit1704 reads the main content and the sub content from theportable medium13 via the third access unit1703 (Step S155). Then, thecontrol unit1704 causes thereproduction unit1705 to reproduce the main content and the sub content read from the portable medium13 by associating them with each other (Step5156). The reproduced data is outputted to the outside via themonitor171 and thespeaker172. As such, the operation of thereproduction apparatus17 ends.

Verification of Operation ofAggregation System1

The overall operation of theaggregation system1 in the first embodiment will be summarized below.

First, theaggregation apparatus16 reads the main content and the reproduction judgment information from theoptical disc11 and reads the sub content from thememory card12. When the value of the reproduction judgment information read from theoptical disc11 is 1, theaggregation apparatus16 aggregates the main content and the sub content and records them onto theportable medium13, and rewrites the value of the reproduction judgment information on theoptical disc11 to another value than 1.

When reproducing the main content recorded on theoptical disc11 and the sub content recorded on thememory card12, thereproduction apparatus17 reads the main content and the reproduction judgment information from theoptical disc11 and reads the sub content from thememory card12. When the value of the reproduction judgment information is 1, thereproduction apparatus17 causes thereproduction unit1705 to reproduce the main content and the sub content by associating them with each other and output the reproduced data to the outside.

On the other hand, when reproducing the main content and the sub content which are recorded on theportable medium13, thereproduction apparatus17 reads the main content and the sub content from theportable medium13, and causes thereproduction unit1705 to reproduce both the contents by associating them with each other.

As a result, the user can reproduce the main content recorded on theoptical disc11 and the sub content recorded on thememory card12 by associating them with each other. In addition, for the sake of enhancing convenience of portability, the user can reproduce the main content and the sub content which are recorded on the portable medium13 by associating them with each other by aggregating the main content recorded on theoptical disc11 and the sub content recorded on thememory card12 and recording them on theportable medium13.

Effect Obtained in First Embodiment

In the first embodiment, after aggregating the main content recorded on theoptical disc11 and the sub content recorded on thememory card12 and recording them onto theportable medium13, theaggregation apparatus16 rewrites the reproduction judgment information recorded on theoptical disc11 from 1 to another value than 1. When the value of the reproduction judgment information recorded on theoptical disc11 is another value than 1, thereproduction apparatus17 does not reproduce the main content recorded on theoptical disc11.

Thereby, in a case where the main content and the sub content are aggregated and recorded onto theportable medium13, the main content and the sub content recorded on the portable medium13 can be reproduced, but the main content recorded on theoptical disc11 cannot be reproduced. As a result, differently from the conventional techniques, even if theaggregation apparatus16 aggregates the main content recorded on theoptical disc11 and the sub content recorded on thememory card12 and records them onto theportable medium13, the main content which has been recorded on theoptical disc11 before the aggregation is not reproduced after the aggregation. Therefore, the copyrights of the contents are protected.

Modifications

Although the first embodiment has been fully described by way of one example of the embodiments of the present invention, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein. The embodiment of the present invention also includes the following modifications:

(1) As shown inFIG. 7, in a case where, as index information, information necessary for reading the main content from anoptical disc11a, such as information of a table of contents (TOC) for a file system of a DVD and a CD, is recorded on theoptical disc11a, theaggregation apparatus16 may delete or rewrite the index information on theoptical disc11aafter aggregating and recording the main content and the sub content on theportable medium13, in order to prevent reproduction of the main content recorded on theoptical disc11a.

To be more specific, it is assumed, for example, that the TOC information as an example of the index information, as well as the main content, is recorded on theoptical disc11a, as shown inFIG. 7. In theaggregation apparatus16, thecontrol unit163 reads the main content from the optical disc Ha via thefirst access unit161, reads the sub content from thememory card12 via thesecond access unit162, and writes the main content and the sub content on theportable medium13 via thethird access unit164. Then, thecontrol unit163 deletes the TOC information on theoptical disc11avia thefirst access unit161.

In thereproduction apparatus17, when reproducing the main content recorded on theoptical disc11aand the sub content recorded on thememory card12, thecontrol unit1704 reads the main content and the TOC information from theoptical disc11avia thefirst access unit1701, and reads the sub content from thememory card12 via thesecond access unit1702. If the TOC information is not deleted, thecontrol unit1704 causes thereproduction unit1705 to reproduce the main content recorded on theoptical disc11aand the sub content recorded on thememory card12 by associating them with each other and output the reproduced data to the outside via themonitor171 and thespeaker172.

On the other hand, in a case where the main content and the sub content which are recorded on the portable medium13 are reproduced, thecontrol unit1704 reads the main content and the sub content from theportable medium13 via thethird access unit1703, and causes thereproduction unit1705 to reproduce the main content and the sub content by associating them with each other and output the reproduced data to the outside via themonitor171 and thespeaker172.

Thereby, after the aggregation of the main content and the sub content, the TOC information on theoptical disc11ais deleted and the main content recorded on theoptical disc11acannot be reproduced, so the same effect as that of the first embodiment can be obtained. Note that although the above explanation is based on the assumption that the TOC information is deleted, the index information such as the TOC information may be rewritten. The same effect can be obtained in either the case where the index information is deleted or rewritten. In addition, not only the index information is deleted or rewritten, but also the main content may be deleted or rewritten.

(2) Furthermore,FIG. 8 shows an example where an encrypted main content and a decryption key for the main content are recorded on anoptical disc11b. In this case, after aggregating the main content and the sub content, theaggregation apparatus16 may delete or rewrite the decryption key on theoptical disc11b.

To be more specific, an encrypted main content ECNT=Sym (K, CNT) and a decryption key K′ are recorded on theoptical disc11b. The encrypted main content is generated by applying a common key encryption algorithm Sym like a DES encryption method to a main content CNT using an encryption key K. In the common key encryption algorithm, the encryption key K and the decryption key K′ have the same value.

In theaggregation apparatus16, thecontrol unit163 reads the encrypted main content ECNT and the decryption key K′ from theoptical disc11bvia thefirst access unit161, reads the sub content SCNT from thememory card12 via thesecond access unit162, and writes the encrypted main content ECNT, the decryption key K′ and the sub content SCNT onto theportable medium13 via thethird access unit164. Then, thecontrol unit163 deletes the decryption key K′ on theoptical disc11bvia thefirst access unit161.

In thereproduction apparatus17, thecontrol unit1704 has the common key encryption algorithm Sym which was used for encrypting the main content CNT. When reproducing the main content recorded on theoptical disc11band the sub content recorded on thememory card12, thecontrol unit1704 reads the encrypted main content ECNT and the decryption key K′ from theoptical disc11bvia thefirst access unit1701, and reads the sub content SCNT from thememory card12 via thesecond access unit1702. If the decryption key K′ has not been deleted, thecontrol unit1704 decrypts the encrypted main content ECNT into the main content CNT=Sym (K′, ECNT) by applying the common key encryption algorithm Sym to the encrypted main content ECNT using the decryption key K′. Then, thecontrol unit1704 causes thereproduction unit1705 to reproduce the decrypted main content, namely, the main content recorded on theoptical disc11band the sub content recorded on thememory card12 by associating them with each other and output the reproduced data to the outside via themonitor171 and thespeaker172.

On the other hand, when reproducing the main content and the sub content which are recorded on theportable medium13, thecontrol unit1704 reads the encrypted main content ECNT, the decryption key K′ and the sub content SCNT from theportable medium13 via thethird access unit1703, and decrypts the encrypted main content ECNT into the main content CNT=Sym (K′, ECNT) by applying the common key encryption algorithm Sym to the encrypted main content ENCT using the decryption key K′. Then, thecontrol unit1704 causes thereproduction unit1705 to reproduce the decrypted main content and the sub content by associating them with each other and output the reproduced data to the outside via themonitor171 and thespeaker172.

As for the common key encryption method and the DES encryption method, “Gendai Angou” (in Japanese) written by Tatsuaki Okamoto and Hirosuke Yamamoto (Series/Jouhou Kagaku no Suugaku, Sangyo Tosho, 1997) presents a detailed description thereof, so the detailed explanation is not repeated here.

Thereby, after the aggregation of the main content and the sub content, the decryption key recorded on theoptical disc11bis deleted and the encrypted main content recorded on theoptical disc11bcannot be decrypted properly, namely, cannot be reproduced, so the same effect as that in the first embodiment can be obtained. Note that although the above explanation is based on the assumption that the decryption key K′ is deleted, the decryption key K′ may be rewritten. The same effect can be obtained in either the case where the decryption key is deleted or rewritten. In addition, not only the decryption key is deleted or rewritten, but also the encrypted main content may be deleted or rewritten.

Note that an encryption algorithm to be used is not limited to the common key encryption algorithm, but may be a public key encryption algorithm.

(3) Furthermore, in the above-mentioned modification (2), theaggregation apparatus16 may decrypt the encrypted main content ECNT. To be more specific, in theaggregation apparatus16, thecontrol unit163 has the common key encryption algorithm Sym, and decrypts the encrypted main content ECNT into the main content CNT by applying the common key encryption algorithm Sym to the encrypted main content ECNT using the decryption key K′. Thecontrol unit163 also writes the decrypted main content CNT and the sub content SCNT onto theportable medium13 via thethird access unit164.

When reproducing the main content recorded on theoptical disc11band the sub content recorded on thememory card12, in thereproduction apparatus17, thecontrol unit1704 reads the encrypted main content ECNT and the decryption key K′ from theoptical disc11bvia thefirst access unit1701, and reads the sub content SCNT from thememory card12 via thesecond access unit1702, as mentioned above. If the decryption key K′ has not been deleted, thecontrol unit1704 decrypts the encrypted main content ECNT into the main content CNT=Sym (K′, ECNT) by applying the common key encryption algorithm Sym to the encrypted main content ECNT using the decryption key K′. Then, thecontrol unit1704 causes thereproduction unit1705 to reproduce the decrypted main content, namely, the main content recorded on theoptical disc11b, and the sub content recorded on thememory card12 by associating them with each other and output the reproduced data to the outside via themonitor171 and thespeaker172.

On the other hand, when reproducing the main content and the sub content which are recorded on theportable medium13, thecontrol unit1704 reads the main content CNT and the sub content SCNT from theportable medium13 via thethird access unit1703. Then, thecontrol unit1704 causes thereproduction unit1705 to reproduce the main content CNT and the sub content SCNT by associating them with each other and output the reproduced data to the outside via themonitor171 and thespeaker172.

Thereby, the same effect as that in the first embodiment can be obtained, as is the case with the modification (2).

(4) Furthermore,FIG. 9 shows an example where anoptical disc11cis equipped with a fuse for blocking the reproduction of theoptical disc11cif it is destroyed. In this case, theaggregation apparatus16 may destroy the fuse in theoptical disc11cafter aggregating the main content and the sub content so as to block the reproduction of theoptical disc11c. This can be realized if, for example, thefirst access unit161 in theaggregation apparatus16 destroys the fuse by irradiating an intense laser beam to theoptical disc11c.

To be more specific, theoptical disc11cmay be equipped with an IC chip for making non-contact communication with the outside as an example of a scheme for blocking the reproduction of theoptical disc11cif it is destroyed. In this case, after the aggregation of the main content and the sub content, thefirst access unit161 in theaggregation apparatus16 destroys the IC chip in theoptical disc11cby irradiating an intense laser beam on it.

Thereby, after the aggregation of the main content and the sub content, the IC chip provided in theoptical disc11cis destroyed and the main content recorded on theoptical disc11ccannot be reproduced, so the same effect as that in the first embodiment can be obtained.

Note that not only the fuse is destroyed, but also the storage area of the main content may be destroyed.

(5) Furthermore, in a case where there exist a set of a plurality of main contents and reproduction judgment information on theoptical disc11, theaggregation apparatus16 may aggregate a plurality of the main contents which exist on theoptical disc11 and one or more sub contents which exist on thememory card12 and record them onto theportable medium13. This can be realized as follows. For example, in theaggregation apparatus16, thecontrol unit163 reads a plurality of main contents via thefirst access unit161, reads one or more sub contents via thesecond access unit162, records the plurality of main contents and one or more sub contents onto theportable medium13 via thethird access unit164 depending on the value of the reproduction judgment information on theoptical disc11, and rewrites the reproduction judgment information on theoptical disc11 via thefirst access unit161.

Thereby, it becomes possible to aggregate a plurality of contents of a series or the like and one or more sub contents.

In addition, if a plurality of contents which are viewed repeatedly are aggregated and recorded onto a hard disk or the like using this method, there is no need to swap storage mediums in and out of thereproduction apparatus17, and thus convenience for users is enhanced.

(6) The default value of the reproduction judgment information to be recorded on theoptical disc11 may be another value than 1. In short, the default value of the reproduction judgment information must be a value indicating that reproduction is permitted.

For example, in a case where the default value of the reproduction judgment information is “Yes”, after thecontrol unit163 in theaggregation apparatus16 aggregates the main content on theoptical disc11 and the sub content on thememory card12 and records them onto theportable medium13, the value of the reproduction judgment information may be rewritten to “No”.

Note that the format of the information recorded on theoptical disc11 may be same as the format of the information recorded on the portable medium13 or the recording medium that replaces theportable medium13. For example, the information is recorded on any recording mediums in MPEG-2 data format.

Second Embodiment

Next, anaggregation system2 in the second embodiment of the present invention will be explained below with reference toFIG. 10 toFIG. 14.

When an aggregation apparatus aggregates contents recorded on a plurality of recording mediums and records them onto another recording medium, thisaggregation system2 does not reproduce, after the aggregation, the contents which have been recorded on the source recording mediums and the contents aggregated and recorded onto another recording medium at the same time.

Overview ofAggregation System2

First, the overview of theaggregation system2 in the second embodiment will be provided with reference toFIG. 10.FIG. 10 is a block diagram showing the configuration of theaggregation system2 in the second embodiment.

InFIG. 10, a content such as a movie is recorded, in encrypted form, as a main content, on anoptical disc21, and a decryption key for decrypting the encrypted main content is recorded on a decryptionkey storage medium211. A sub content such as audio data to be used in association with the main content recorded on theoptical disc21 can be recorded on amemory card22, and aportable medium23 is a portable medium such as a DVD-RAM on which information can be recorded. Note that the portable medium23 may be a removable HDD, or may be replaced with a recording medium such as a nonremovable HDD.

A content provider distributes the encrypted main content to a user via a distribution means such as a sale of the encrypted main content recorded on theoptical disc21, together with the decryptionkey storage medium211, and distributes the sub content to be used in association with the main content from aserver24 via theInternet28.

On the other hand, the user obtains the sub content from theserver24 via theInternet28 using a subcontent obtainment apparatus25, and records it on thememory card22. Then, on areproduction apparatus27, the user decrypts the encrypted main content recorded on theoptical disc21 using the decryption key recorded on the decryptionkey storage medium211, reproduces the decrypted main content by associating it with the sub content recorded on thememory card22, and views it.

In order to enhance convenience of portability, the user can also aggregate both the encrypted main content recorded on theoptical disc21 and the sub content recorded on thememory card22 and record them onto theportable medium23, using anaggregation apparatus26. On thereproduction apparatus27, the user can also reproduce and view the encrypted main content and the sub content which are recorded on theportable medium23, using the decryption key recorded on the decryptionkey storage medium211. It is assumed that the decryption key recorded on the decryptionkey storage medium211 cannot be copied onto another recording medium and the decryption key recorded on the decryptionkey storage medium211 is necessary for reproducing the content recorded on theoptical disc21 and the content recorded on theportable medium23. Thereby, theaggregation system2 does not reproduce the content recorded on theoptical disc21 and the content recorded on the portable medium23 at the same time on a plurality of reproduction apparatuses.

In other words, thisaggregation system2 is a system for protecting copyrights of contents by not reproducing contents recorded on a plurality of recording mediums and the contents aggregated and recorded onto another recording medium at the same time, after a user aggregates the contents recorded on the plurality of recording mediums and record them onto another recording medium.

The overview of theaggregation system2 in the second embodiment has been provided, and the detailed explanation of theaggregation system2 will follow.

Configuration ofAggregation System2

As shown inFIG. 10, theaggregation system2 includes theoptical disc21, the decryptionkey storage medium211, thememory card22, theportable medium23, theserver24, the subcontent obtainment apparatus25, theaggregation apparatus26 and thereproduction apparatus27, and theserver24 and the subcontent obtainment apparatus25 are connected to each other via theInternet28.

Structure ofOptical Disc21

Theoptical disc21 is a portable medium, such as a DVD-RAM, on which information can be recorded, and an encrypted main content is recorded here.

To be more specific, an encrypted main content ECNT=Sym (K, CNT) is recorded on theoptical disc21. This encrypted main content is generated by applying a common key encryption algorithm Sym like a DES encryption method, as an example of encryption method, to a main content CNT using an encryption key K. The following explanation will be made using this example.

As for the common key encryption method and the DES encryption method, “Gendai Angou” (in Japanese) written by Tatsuaki Okamoto and Hirosuke Yamamoto (Series/Jouhou Kagaku no Suugaku, Sangyo Tosho, 1997) presents a detailed description thereof, so the detailed explanation is not repeated here.

Structure of DecryptionKey Storage Medium211

The decryptionkey storage medium211 is a storage medium, such as an SD card, on which information can be recorded. On this decryptionkey storage medium211, a decryption key for decrypting an encrypted main content recorded on theoptical disc21 is recorded. It is assumed here that the decryption key recorded on the decryptionkey storage medium211 cannot be copied.

To be more specific, it is assumed that a decryption key K′ which corresponds to the encryption key K is recorded on the decryptionkey storage medium211. Note that the encryption key K and the decryption key K′ have the same value in the common key encryption algorithm.

Structure ofMemory Card22

Thememory card22 is a recording medium, such as an SD card, on which information can be recorded. On thememory card22, a sub content to be used in association with the main content is recorded by the subcontent obtainment apparatus25.

Structure ofPortable Medium23

Theportable medium23 is a portable medium, such as a DVD-RAM, on which information can be recorded. The encrypted main content recorded on theoptical disc21 and the sub content recorded on thememory card22 are aggregated and recorded onto the portable medium23 by theaggregation apparatus26. Note that, as mentioned above, the portable medium23 may be a removable HDD, or may be replaced with a recording medium such as a nonremovable HDD. In short, the portable medium23 or the recording medium that replaces the portable medium23 must be a recording medium on which aggregated main content and sub content are recorded.

Structure ofServer24

Theserver24 holds the sub content to be used in association with the main content obtained by decrypting the encrypted main content recorded on theoptical disc21, and provides the subcontent obtainment apparatus25 with the sub content.

Structure of SubContent Obtainment Apparatus25

The subcontent obtainment apparatus25 obtains the sub content from theserver24 via theInternet28, and records it on thememory card22.

Structure ofAggregation Apparatus26

FIG. 11 shows the structure of theaggregation apparatus26. As shown inFIG. 11, theaggregation apparatus26 includes afirst access unit261, asecond access unit262, acontrol unit263, athird access unit264, aninput unit265 and adisplay unit266.

(1)First Access Unit261

Thefirst access unit261 reads the encrypted main content from theoptical disc21 according to the instruction of thecontrol unit263.

(2)Second Access Unit262

Thesecond access unit262 reads the sub content from thememory card22 according to the instruction of thecontrol unit263.

(3)Control Unit263

Thecontrol unit263 reads the encrypted main content from theoptical disc21 via thefirst access unit261, and reads the sub content from thememory card22 via thesecond access unit262.

Then, thecontrol unit263 writes the encrypted main content and the sub content onto theportable medium23 via thethird access unit264.

(4)Third Access Unit264

Thethird access unit264 writes the encrypted main content and the sub content onto the portable medium23 according to the instruction of thecontrol unit263.

(5)Input Unit265

Theinput unit265 accepts an input of an aggregation instruction from a user.

Then, upon receipt of the input of the aggregation instruction from the user, theinput unit265 causes thecontrol unit263 to operate.

(6)Display Unit266

After thecontrol unit263 completes writing the encrypted main content and the sub content onto theportable medium23, thedisplay unit266 notifies the user of the end of the writing by displaying it.

Structure ofReproduction Apparatus27

FIG. 12 shows the structure of thereproduction apparatus27. As shown inFIG. 12, thereproduction apparatus27 includes afirst access unit2701, asecond access unit2702, athird access unit2703, acontrol unit2704, areproduction unit2705, aninput unit2706 and a decryptionkey access unit2707.

(1)First Access Unit2701

Thefirst access unit2701 reads the encrypted main content from theoptical disc21 according to the instruction of thecontrol unit2704.

(2)Second Access Unit2702

Thesecond access unit2702 reads the sub content from thememory card22 according to the instruction of thecontrol unit2704.

(3)Third Access Unit2703

Thethird access unit2703 reads the encrypted main content and the sub content from the portable medium23 according to the instruction of thecontrol unit2704.

(4)Control Unit2704

Thecontrol unit2704 performs either the following processing (i) or (ii) according to the instruction of theinput unit2706.

(i) To cause thereproduction unit2705 to reproduce the main content obtained by decrypting the encrypted main content recorded on theoptical disc21 and the sub content recorded on thememory card22 by associating them with each other.

Thecontrol unit2704 reads the encrypted main content from theoptical disc21 via thefirst access unit2701, reads the sub content from thememory card22 via thesecond access unit2702, and further reads the decryption key from the decryptionkey storage medium211 via the decryptionkey access unit2707. Then, thecontrol unit2704 decrypts the encrypted main content using the decryption key, and causes thereproduction unit2705 to reproduce the main content obtained by the decryption and the sub content by associating them with each other and output the reproduced data to the outside.

As a specific decryption method, thecontrol unit2704, which has the common key encryption algorithm Sym used for encrypting the main content CNT, decrypts the encrypted main content ECNT into the main content CNT=Sym (K′, ECNT) using the decryption key K′ read from the decryptionkey storage medium211.

It is assumed in the second embodiment that the main content is digital data composed of audio data and video data and the sub content is digital data composed of audio data, for example. In this case, thecontrol unit2704 causes thereproduction unit2705 to replace the audio data in the main content with the audio data in the sub content, so that the main content recorded on theoptical disc21 and the sub content recorded on thememory card22 are reproduced in association with each other.

(ii) To cause thereproduction unit2705 to reproduce the main content obtained by decrypting the encrypted main content recorded on theportable medium23 and the sub content recorded on the portable medium23 by associating them with each other.

Thecontrol unit2704 reads the encrypted main content and the sub content from theportable medium23 via thethird access unit2703, and reads the decryption key from the decryptionkey storage medium211 via the decryptionkey access unit2707. Then, thecontrol unit2704 decrypts the encrypted main content using the decryption key, and causes thereproduction unit2705 to reproduce the main content obtained by the decryption and the sub content by associating them with each other and output the reproduced data to the outside.

Note that the specific decryption method and the method for reproducing the main content and the sub content by associating them with each other are same as that in the above (i).

(5)Reproduction Unit2705

Thereproduction unit2705 reproduces the main content and the sub content by associating them with each other under the control of thecontrol unit2704, and outputs the reproduced data to amonitor271 and aspeaker272 which are connected to thereproduction unit2705. Themonitor271 and thespeaker272 output the data reproduced by thereproduction unit2705 to the outside.

(6)Input Unit2706

Theinput unit2706 accepts an instruction to reproduce theoptical disc21 or an instruction to reproduce the portable medium23 from the user.

Upon receipt of the instruction to reproduce theoptical disc21, theinput unit2706 causes thecontrol unit2704 to operate so that the main content obtained by decrypting the encrypted main content recorded on theoptical disc21 and the sub content recorded on thememory card22 are reproduced in association with each other.

On the other hand, upon receipt of the instruction to reproduce theportable medium23, theinput unit2706 causes thecontrol unit2704 to operate so that the main content obtained by decrypting the encrypted main content recorded on theportable medium23 and the sub content recorded on the portable medium23 are reproduced in association with each other.

(7) DecryptionKey Access Unit2707

The decryptionkey access unit2707 reads a decryption key from the decryptionkey storage medium211 according to the instruction of thecontrol unit2704.

Operation ofAggregation System2

The configuration of theaggregation system2 has been explained, and the detailed explanation of the operations of theaggregation apparatus26 and thereproduction apparatus27, as the operation of theaggregation system2, will follow.

Operation ofAggregation Apparatus26

The operation of theaggregation apparatus26 will be explained with reference to the flowchart as shown inFIG. 13.

When theinput unit265 receives the input of the aggregation instruction from the user, theaggregation apparatus26 performs the following processing.

First, thecontrol unit263 reads the encrypted main content from theoptical disc21 via thefirst access unit261, and reads the sub content from thememory card22 via the second access unit262 (Step S201).

Next, thecontrol unit263 writes the encrypted main content and the sub content onto theportable medium23 via the third access unit264 (Step S202).

Next, thedisplay unit266 displays that writing of the encrypted main content and the sub content onto theportable medium23 has been completed (Step S203). Then, the operation of theaggregation apparatus26 ends.

Operation ofReproduction Apparatus27

The operation of thereproduction apparatus27 will be explained with reference to the flowchart as shown inFIG. 14.

When theinput unit2706 receives the instruction to reproduce theoptical disc21 or the instruction to reproduce the portable medium23 from the user, thereproduction apparatus27 performs the following operation.

First, theinput unit2706 checks whether the received reproduction instruction is the instruction to reproduce theoptical disc21 or the instruction to reproduce the portable medium23 (Step S251). The processing goes to Step S252 in the case of the instruction to reproduce theoptical disc21, whereas the processing goes to Step S254 in the case of the instruction to reproduce theportable medium23.

To be more specific, in a case where the reproduction instruction received by theinput unit2706 is the instruction to reproduce the optical disc21 (No in Step S251), thecontrol unit2704 reads the encrypted main content from theoptical disc21 via thefirst access unit2701, reads the sub content from thememory card22 via thesecond access unit2702, and further reads the decryption key from the decryptionkey storage medium211 via the decryption key access unit2707 (Step S252).

Next, thecontrol unit2704 decrypts the encrypted main content using the decryption key, and causes thereproduction unit2705 to reproduce the main content obtained by the decryption and the sub content by associating them with each other (Step S253). The reproduced data is outputted to the outside via themonitor271 and thespeaker272. As such, the operation of thereproduction apparatus27 ends.

On the other hand, in a case where the reproduction instruction received by theinput unit2706 is the instruction to reproduce the portable medium23 (Yes in Step S251), thecontrol unit2704 reads the encrypted main content and the sub content from theportable medium23 via thethird access unit2703, and reads the decryption key from the decryptionkey storage medium211 via the decryption key access unit2707 (Step S254). Then, thecontrol unit2704 decrypts the encrypted main content using the decryption key, and causes thereproduction unit2705 to reproduce the main content obtained by the decryption and the sub content by associating them with each other (Step S255). The reproduced data is outputted to the outside via themonitor271 and thespeaker272. As such, the operation of thereproduction apparatus27 ends.

Verification of Operation ofAggregation System2

The overall operation of theaggregation system2 in the second embodiment will be summarized below.

First, theaggregation apparatus26 reads the encrypted main content from theoptical disc21, reads the sub content from thememory card22, and records the encrypted main content and the sub content onto theportable medium23.

When reproducing the encrypted main content recorded on theoptical disc21 and the sub content recorded on thememory card22, thereproduction apparatus27 reads the encrypted main content from theoptical disc21, reads the sub content from thememory card22, reads the decryption key from the decryptionkey storage medium211, and then decrypts the encrypted main content using the decryption key. Then, thereproduction apparatus27 causes thereproduction unit2705 to reproduce the main content obtained by the decryption and the sub content by associating them with each other and output the reproduced data to the outside.

On the other hand, when reproducing the encrypted main content and the sub content which are recorded on theportable medium23, thereproduction apparatus27 reads the encrypted main content and the sub content from theportable medium23, further reads the decryption key from the decryptionkey storage medium211, and decrypts the encrypted main content using the decryption key. Then, thereproduction apparatus27 causes thereproduction unit2705 to reproduce both the main content obtained by the decryption and the sub content by associating them with each other and output the reproduced data to the outside.

As a result, the user can reproduce the encrypted main content recorded on theoptical disc21 and the sub content recorded on thememory card22 by associating them with each other. In addition, for the sake of enhancing convenience of portability, the user can aggregate the main content recorded on theoptical disc21 and the sub content recorded on thememory card22 and record them onto theportable medium23, and reproduce the main content and the sub content which are recorded on the portable medium23 by associating them with each other.

Effect Obtained in Second Embodiment

In the second embodiment, the main content is recorded, in encrypted form, on theoptical disc21 or theportable medium23, and thereproduction apparatus27 reads an uncopyable decryption key from the decryptionkey storage medium211 so as to reproduce the main content.

Thereby, in a case where the main content and the sub content are aggregated and recorded onto theportable medium23, the decryptionkey storage medium211 is required for the reproduction of the main content, so neither the main content recorded on theoptical disc21 nor the main content recorded on the portable medium23 can be reproduced at the same time on a plurality of reproduction apparatuses. As a result, differently from the conventional techniques, even if theaggregation apparatus26 aggregates the main content recorded on theoptical disc21 and the sub content recorded on thememory card22 and records them onto theportable medium23, the main content recorded on theoptical disc21 and the main content recorded on the portable medium23 are not reproduced at the same time. Therefore, the copyrights of the contents are protected.

Modifications

Although the second embodiment has been fully described by way of one example of the embodiments of the present invention, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein. The embodiment of the present invention also includes the following modifications:

(1) In a case where a plurality of main contents a, b and c are recorded, in encrypted form, on a plurality ofoptical discs21a,21band21c, decryption keys a, b and c for the main contents a, b and c are respectively recorded on a plurality of decryption key storage mediums211a,211band211c, as shown inFIG. 15. In order to enhance convenience of portability, it is also possible to record the decryption keys a, b and c on a decryption key storage medium211dcollectively and then delete the decryption keys a, b and c recorded on the source decryption key storage mediums211a,211band211c.

Thereby, the same effect as that in the second embodiment can be obtained. In addition, when a user carries a plurality of optical discs, the number of decryptionkey storage mediums211 to be carried for reproducing such discs can be reduced, so the user convenience is enhanced.

(2)FIG. 17 shows an example where the decryption key, which is recorded on the decryptionkey storage unit211 in the present embodiment, is recorded on theoptical disc21a, together with the encrypted main content. Theaggregation apparatus26 aggregates the encrypted main content recorded on theoptical disc21aand the sub content recorded on thememory card22 and records them onto theportable medium23. To be more specific, theoptical disc21 is required for reproduction of the encrypted main content recorded on theportable medium23, because the decryption key needs to be read from theoptical disc21.

Thereby, the main content recorded on theoptical disc21 and the main content recorded on the portable medium23 are not reproduced at the same time on a plurality of reproduction apparatuses, so the same effect as that in the second embodiment can be obtained.

(3) The decryption key is not recorded on the decryptionkey storage medium211, but may be obtained from theserver24 via theInternet28 when thereproduction apparatus27 reproduces theoptical disc21 or theportable medium23.

Thereby, there is no need to distribute the decryptionkey storage medium211, nor for the user to manage the decryptionkey storage medium211, so the convenience is enhanced.

(4) With respect to the above (3), it is also possible, for example, that unique medium IDs are respectively recorded on theoptical disc21 and theportable medium23, as shown inFIG. 18, and theserver24 manages, for each medium ID, a set of the medium ID of theoptical disc21 and the decryption key for the encrypted main content recorded on thatoptical discs21, as a decryption key list as shown inFIG. 19.

In this case, when aggregating the contents, theaggregation apparatus26 sends the medium ID of theoptical disc21 and the medium ID of the portable medium23 to theserver24 via theInternet28, and theserver24 adds the medium ID of the portable medium23 to the entry including the medium ID of theoptical disc21. For example, in a case where the main content recorded on theoptical disc21 with its medium ID being 1 is aggregated and recorded onto the portable medium23 with its medium ID being 5, the decryption key list as shown inFIG. 20 is obtained.

When reproducing theoptical disc21 or theportable medium23, thereproduction apparatus27 sends the medium ID of theoptical disc21 or the portable medium23 to theserver24 to request theserver24 to send the corresponding decryption key. Theserver24 checks, using the received medium ID, whether or not the decryption key is used at the same time for reproduction of theoptical disc21 and theportable medium23. To be more specific, this can be realized by checking whether or not both the medium ID of theoptical disc21 and the medium ID of the portable medium23 are used in a predetermined period of time, for example, 2 hours. If both the medium IDs are not used at the same time, theserver24 sends the corresponding decryption key to thereproduction apparatus27.

Thereby, after aggregating the main content and the sub content, the encrypted main content recorded on theoptical disc21 cannot be decrypted at the same time when the encrypted main content recorded on theportable medium23 is decrypted. Therefore, the same effect as that in the second embodiment can be obtained.

Note that the medium ID may be any other ID as long as it can identify what the content recorded on theoptical disc21 is. For example, it may be a content name, a content ID or the like.

(5) Furthermore, as for the decryption key which is recorded on the decryptionkey storage medium211 in the present embodiment, thereproduction apparatus27 may obtain it from theserver24 via theInternet28 and records it on the decryptionkey storage medium211, when theoptical disc21 is reproduced for the first time.

Thereby, there is no need to distribute the decryptionkey storage medium211 on which the decryption key is recorded, and the same effect as that in the second embodiment can be obtained even if thereproduction apparatus27 is not in the environment where it can access theserver24 all the time via theInternet28.

(6) Furthermore, it is also possible that there exist a plurality of encrypted contents on theoptical disc21 and there exist a plurality of the corresponding decryption keys on the decryptionkey storage medium211. Theaggregation apparatus26 aggregates the plurality encrypted main contents and one or more sub contents which exist on thememory card22 and records them onto theportable medium23. This can be realized, for example, if thecontrol unit263 in theaggregation apparatus26 reads a plurality of main contents via thefirst access unit261, reads one or more sub contents via thesecond access unit262, and records the plurality of main contents and one or more sub contents onto theportable medium23 via thethird access unit264.

Thereby, it becomes possible to aggregate a plurality of contents of a series or the like and one or more sub contents.

In addition, if a plurality of contents which are to be viewed repeatedly are aggregated and recorded on a hard disk or the like using this method, there is no need to swap storage mediums in and out of thereproduction apparatus27, and thus convenience for users is enhanced more.

Third Embodiment

Next, anaggregation system3 in the third embodiment of the present invention will be explained below with reference toFIG. 21 toFIG. 27.

When an aggregation apparatus aggregates contents recorded on a plurality of recording mediums and records them onto another recording medium, thisaggregation system3 aggregates the contents and records them onto another recording medium based on aggregation judgment information, managed by the content provider, indicating whether aggregation of the contents is permitted or not.

Overview ofAggregation System3

First, the overview of theaggregation system3 in the third embodiment will be provided with reference toFIG. 21.FIG. 21 is a block diagram showing the configuration of theaggregation system3 in the third embodiment.

InFIG. 21, a content such as a movie is recorded, as a main content, on anoptical disc31, a sub content such as audio data to be used in association with the main content recorded on theoptical disc31 can be recorded on amemory card32, and aportable medium33 is a portable medium such as a DVD-RAM on which information can be recorded. The portable medium33 may be a removable HDD, or may be replaced with a recording medium such as a nonremovable HDD.

A content provider distributes the main content to a user via a distribution means such as a sale of the main content recorded on theoptical disc31, and distributes the sub content to be used in association with the main content to the user from aserver34 via theInternet38.

On the other hand, the user obtains the sub content from theserver34 via theInternet38 using a subcontent obtainment apparatus35, and records it on thememory card32. Then, using areproduction apparatus37, the user reproduces the main content recorded on theoptical disc31 by associating it with the sub content recorded on thememory card32, and views it.

In order to enhance convenience of portability, the user can access theserver34 via theInternet38 and receive aggregation judgment information indicating whether or not aggregation of the main content is permitted, using anaggregation apparatus36. The user can also record, on theportable medium33, the main content recorded on theoptical disc31 and the sub content recorded on thememory card32, based on the aggregation judgment information. The user can also reproduce and view the main content and the sub content which are recorded on the portable medium33 by associating them with each other, using thereproduction apparatus37.

Thisaggregation system3 is a system for protecting copyrights of contents by putting limitations on a user's aggregation and recording of contents recorded on a plurality of recording mediums onto another recording medium, based on aggregation judgment information, managed by a content provider, indicating whether or not aggregation of the contents is permitted.

The overview of theaggregation system3 in the third embodiment has been provided, and the detailed explanation of theaggregation system3 will follow.

Configuration ofAggregation System3

As shown inFIG. 21, theaggregation system3 includes theoptical disc31, thememory card32, theportable medium33, theserver34, the subcontent obtainment apparatus35, theaggregation apparatus36 and thereproduction apparatus37, and theserver34 and the subcontent obtainment apparatus35 are connected to each other via theInternet38. Theserver34 is also connected with theaggregation apparatus36 via theInternet38.

Structure ofOptical Disc31

Theoptical disc31 is a portable medium such as a DVD-RAM on which information can be recorded. As shown inFIG. 22, a main content is recorded on theoptical disc31. And a medium ID for identifying theoptical disc31 uniquely is also recorded on theoptical disc31 when it is manufactured.

Here, the medium ID can be read by theaggregation apparatus36 and thereproduction apparatus37, but cannot be rewritten nor deleted.

Structure ofMemory Card32

Thememory card32 is a recording medium such as an SD card on which information can be recorded. On thememory card32, a sub content to be used in association with the main content is recorded by the subcontent obtainment apparatus35.

Structure ofPortable Medium33

Theportable medium33 is a portable medium such as a DVD-RAM on which information can be recorded. The main content recorded on theoptical disc31 and the sub content recorded on thememory card32 are aggregated and recorded onto the portable medium33 by theaggregation apparatus36. Note that, as mentioned above, the portable medium33 may be a removable HDD, or may be replaced with a recording medium such as a nonremovable HDD. In short, the portable medium33 or the recording medium that replaces the portable medium33 must be a recording medium on which aggregated main content and sub content are recorded.

Structure ofServer34

Theserver34 holds the sub content to be used in association with the main content recorded on theoptical disc31, and provides the subcontent obtainment apparatus35 with the sub content.

Theserver34 also holds a list of sets of medium IDs and aggregation judgment information, as shown inFIG. 23. The aggregation judgment information indicates whether or not each main content recorded on theoptical disc31 with its medium ID is permitted to be aggregated and recorded onto theportable medium33, together with the sub content.

Upon receipt of the medium ID from theaggregation apparatus36 via theInternet38, theserver34 sends, to theaggregation apparatus36 via theInternet38, the aggregation judgment information of the main content recorded on theoptical disc31 with that medium ID, with reference to the above list of aggregation judgment information.

Structure of SubContent Obtainment Apparatus35

The subcontent obtainment apparatus35 obtains the sub content from theserver34 via theInternet38, and records it on thememory card32.

Structure ofAggregation Apparatus36

FIG. 24 shows the structure of theaggregation apparatus36. As shown inFIG. 24, theaggregation apparatus36 includes afirst access unit361, asecond access unit362, acontrol unit363, athird access unit364, aninput unit365, adisplay unit366 and a sending/receivingunit367.

(1)First Access Unit361

Thefirst access unit361 reads the main content and the medium ID from theoptical disc31 according to the instruction of thecontrol unit363.

(2)Second Access Unit362

Thesecond access unit362 reads the sub content from thememory card32 according to the instruction of thecontrol unit363.

(3)Control Unit363

Thecontrol unit363 reads the main content and the medium ID from theoptical disc31 via thefirst access unit361, and reads the sub content from thememory card32 via thesecond access unit362.

Then, thecontrol unit363 sends the medium ID to theserver34 via the sending/receivingunit367, and receives the aggregation judgment information corresponding to the medium ID from theserver34.

When the aggregation judgment information indicates that the main content is permitted to be aggregated with the sub content and recorded onto theportable medium33, thecontrol unit363 writes the main content and the sub content onto theportable medium33 via thethird access unit364.

(4)Third Access Unit364

Thethird access unit364 writes the main content and the sub content onto the portable medium33 according to the instruction of thecontrol unit363.

(5)Input Unit365

Theinput unit365 accepts an input of an aggregation instruction from a user.

Then, upon receipt of the input of the aggregation instruction from the user, theinput unit365 causes thecontrol unit363 to operate.

(6)Display Unit366

After thecontrol unit363 completes writing of the main content and the sub content onto theportable medium33, thedisplay unit366 notifies the user of the end of the processing by displaying it.

(7) Sending/Receiving Unit367

The sending/receivingunit367 sends the medium ID to theserver34 via theInternet38 according to the instruction of thecontrol unit363, and receives the aggregation judgment information corresponding to the medium ID from theserver34 via theInternet38.

Structure ofReproduction Apparatus37

FIG. 25 shows the structure of thereproduction apparatus37. As shown inFIG. 25, thereproduction apparatus37 includes afirst access unit3701, asecond access unit3702, athird access unit3703, acontrol unit3704, areproduction unit3705, and aninput unit3706.

(1)First Access Unit3701

Thefirst access unit3701 reads the main content from theoptical disc31 according to the instruction of thecontrol unit3704.

(2)Second Access Unit3702

Thesecond access unit3702 reads the sub content from thememory card32 according to the instruction of thecontrol unit3704.

(3)Third Access Unit3703

Thethird access unit3703 reads the main content and the sub content from the portable medium33 according to the instruction of thecontrol unit3704.

(4)Control Unit3704

Thecontrol unit3704 performs either the following processing (i) or (ii) according to the instruction of theinput unit3706.

(i) To cause thereproduction unit3705 to reproduce the main content recorded on theoptical disc31 and the sub content recorded on thememory card32 by associating them with each other.

Thecontrol unit3704 reads the main content from theoptical disc31 via thefirst access unit3701, and reads the sub content from thememory card32 via thesecond access unit3702. Then, thecontrol unit3704 causes thereproduction unit3705 to reproduce the main content and the sub content by associating them with each other and output them to the outside.

(ii) To cause thereproduction unit3705 to reproduce the main content and the sub content which are recorded on the portable medium33 by associating them with each other.

Thecontrol unit3704 reads the main content and the sub content from theportable medium33 via thethird access unit3703. Then, thecontrol unit3704 causes thereproduction unit3705 to reproduce the main content and the sub content by associating them with each other and output them to the outside.

(5)Reproduction Unit3705

Thereproduction unit3705 reproduces the main content and the sub content by associating them with each other under the control of thecontrol unit3704, and outputs the reproduced data to amonitor371 and aspeaker372 which are connected to thereproduction unit3705. Themonitor371 and thespeaker372 output the data reproduced by thereproduction unit3705 to the outside.

(6)Input Unit3706

Theinput unit3706 accepts an instruction to reproduce theoptical disc31 or an instruction to reproduce the portable medium33 from the user.

Upon receipt of the instruction to reproduce theoptical disc31, theinput unit3706 causes thecontrol unit3704 to operate so that the main content recorded on theoptical disc31 and the sub content recorded on thememory card32 are reproduced in association with each other.

On the other hand, upon receipt of the instruction to reproduce theportable medium33, theinput unit3706 causes thecontrol unit3704 to operate so that the main content and the sub content which are recorded on the portable medium33 are reproduced in association with each other.

Operation ofAggregation System3

The configuration of theaggregation system3 has been explained, and the detailed explanation of the operations of theaggregation apparatus36 and thereproduction apparatus37, as the operation of theaggregation system3, will follow.

Operation ofAggregation Apparatus36

The operation of theaggregation apparatus36 will be explained with reference to the flowchart as shown inFIG. 26.

When theinput unit365 receives the input of the aggregation instruction from the user, theaggregation apparatus36 performs the following processing.

First, thecontrol unit363 reads the main content and the medium ID from theoptical disc31 via thefirst access unit361, and reads the sub content from thememory card32 via the second access unit362 (Step S301).

Then, thecontrol unit363 sends the medium ID to theserver34 via the sending/receivingunit367, and receives the aggregation judgment information corresponding to the medium ID from the server34 (Step S302).

Next, thecontrol unit363 checks whether or not the aggregation judgment information indicates that the main content is permitted to be aggregated with the sub content and written onto the portable medium33 (Step S303). When the aggregation judgment information does not indicate that the content is not permitted to be aggregated and written (No in Step S303), the operation of the aggregation apparatus ends.

On the other hand, when the aggregation judgment information indicates that the content is permitted to be aggregated and written (Yes in Step S303), thecontrol unit363 writes the main content and the sub content onto theportable medium33 via the third access unit364 (Step S304).

Next, thedisplay unit366 displays that writing of the main content and the sub content onto theportable medium33 has been completed (Step S305). Thereby, the operation of theaggregation apparatus36 ends.

Operation ofReproduction Apparatus37

The operation of thereproduction apparatus37 will be explained with reference to the flowchart as shown inFIG. 27.

When theinput unit3706 receives the instruction to reproduce theoptical disc31 or the instruction to reproduce the portable medium33 from the user, thereproduction apparatus37 performs the following operation.

First, theinput unit3706 checks whether the received reproduction instruction is the instruction to reproduce theoptical disc31 or the instruction to reproduce the portable medium33 (Step S351). The processing goes to Step S352 in the case of the instruction to reproduce theoptical disc31, whereas the processing goes to Step S354 in the case of the instruction to reproduce theportable medium33.

To be more specific, in the case where the reproduction instruction received by theinput unit3706 is the instruction to reproduce the optical disc31 (No in Step S351), thecontrol unit3704 reads the main content from theoptical disc31 via thefirst access unit3701, and reads the sub content from thememory card32 via the second access unit3702 (Step S352).

Next, thecontrol unit3704 causes thereproduction unit3705 to reproduce the main content and the sub content by associating them with each other (Step S353). The reproduced data is outputted to the outside via themonitor371 and thespeaker372. Thereby, the operation of thereproduction apparatus37 ends.

On the other hand, in the case where the reproduction instruction received by theinput unit3706 is the instruction to reproduce the portable medium33 (Yes in Step S351), thecontrol unit3704 reads the main content and the sub content from theportable medium33 via the third access unit3703 (Step S354). Then, thecontrol unit3704 causes thereproduction unit3705 to reproduce the main content and the sub content by associating them with each other (Step S355). The reproduced data is outputted to the outside via themonitor371 and thespeaker372. Then, the operation of thereproduction apparatus37 ends.

Verification of Operation ofAggregation System3

The overall operation of theaggregation system3 in the third embodiment will be summarized below.

First, theaggregation apparatus36 reads the main content and the medium ID from theoptical disc31, reads the sub content from thememory card32, sends the medium ID to theserver34, and receives the aggregation judgment information corresponding to that medium ID from theserver34. When the aggregation judgment information indicates that the main content is permitted to be aggregated with the sub content and recorded onto theportable medium33, theaggregation apparatus36 records the main content and the sub content onto theportable medium33.

When reproducing the main content recorded on theoptical disc31 and the sub content recorded on thememory card32, thereproduction apparatus37 reads the main content from theoptical disc31, reads the sub content from thememory card32, and causes thereproduction unit3705 to reproduce the main content and the sub content by associating them with each other and output the reproduced data to the outside.

On the other hand, when reproducing the main content and the sub content which are recorded on theportable medium33, thereproduction apparatus37 reads the main content and the sub content from theportable medium33, and causes thereproduction unit3705 to reproduce the main content and the sub content by associating them with each other and output the reproduced data to the outside.

As a result, the user can reproduce the main content recorded on theoptical disc31 and the sub content recorded on thememory card32 by associating them with each other. In addition, for the sake of enhancing convenience of portability, the user can aggregate the main content recorded on theoptical disc31 and the sub content recorded on thememory card32 and record them onto theportable medium33, and reproduce the main content and the sub content which are recorded on the portable medium33 by associating them with each other.

Effect Obtained in Third Embodiment

In the third embodiment, the main content and the medium ID are recorded on theoptical disc31, and theaggregation apparatus36 records the main content and the sub content onto the portable medium33 based on the aggregation judgment information which corresponds to the medium ID.

Thereby, the main content and the sub content cannot be recorded onto the portable medium33 unless the aggregation judgment information indicates that the main content is permitted to be aggregated with the sub content and recorded onto theportable medium33. As a result, differently from the conventional techniques, theaggregation system3 puts limitations on the aggregation of the main content recorded on theoptical disc31 and the sub content recorded on thememory card32 and recording of them onto theportable medium33, based on the aggregation judgment information managed by the content provider. Therefore, the copyrights of the contents are protected.

Modifications

Although the third embodiment has been fully described by way of one example of the embodiments of the present invention, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein. The embodiment of the present invention also includes the following modifications:

(1) The aggregation judgment information is not limited to the information as shown inFIG. 23. Each of a plurality of sub contents may include a sub content ID for identifying each sub content, and the aggregation judgment information may be determined based on a combination of the medium ID and the sub content ID, as shown inFIG. 28. To be more specific, theaggregation apparatus36 sends a sub content ID and a medium ID to theserver34, and theserver34 sends the aggregation judgment information determined based on the medium ID and the sub content ID to theaggregation apparatus36.

Thereby, it is possible to meet the request of the content provider for permitting only the aggregation of a main content with a specified sub content.

(2) As shown inFIG. 29, the aggregation judgment information may be determined based on a medium ID and information indicating whether or not to bill a user for his/her aggregation of contents. To be more specific, theaggregation apparatus36 sends a medium ID and a user ID for identifying each user to theserver34, and theserver34 sends, to theaggregation apparatus36, the aggregation judgment information determined based on the medium ID and the billing information for the user identified by the user ID.

Thereby, it is possible to meet the request of the content provider for permitting only the user who accepts the billing from the content provider to aggregate contents recorded on a plurality of recording mediums and record them onto a single recording medium.

Note that the aggregation judgment information may be determined based on the medium ID and the amount of billing to the user.

(3) As shown inFIG. 30, the aggregation judgment information may be determined based on a medium ID, information indicating whether or not to bill a user for his/her obtainment of a sub content, and information indicating whether or not to bill the user for his/her aggregation of contents. To be more specific, theaggregation apparatus36 sends a user ID for identifying a user and a medium ID to theserver34, and theserver34 sends, to theaggregation apparatus36, the aggregation judgment information determined based on the medium ID, the billing information for the user who is identified by the user ID for his/her obtainment of the sub content, and the billing information for the user who is identified by the user ID for his/her aggregation of contents.

Thereby, it is possible to meet the request of the content provider for permitting only the user who accepts the billing from the content provider to his/her obtainment of the sub content and aggregation of the contents to aggregate the contents recorded on a plurality of recording mediums and record them onto a single recording medium.

(4) Furthermore, as shown inFIG. 31, the aggregation judgment information may be determined based on a predetermined number of user's aggregations of a main content and a sub content. To be more specific, theaggregation apparatus36 sends a user ID for identifying the user and a medium ID to theserver34, and theserver34 sends, to theaggregation apparatus36, the aggregation judgment information determined based on the number of aggregations of the main content and the sub content by the user identified by the medium ID and the user ID. In other words, theserver34 manages the number of receptions of the medium ID from theaggregation apparatus36 as the number of aggregations of the main content and the sub content for each user ID for identifying the user, and theaggregation apparatus36 sends the user ID and the medium ID to theserver34. Then, theserver34 sends, to theaggregation apparatus36, the aggregation judgment information determined based on the number of aggregations of the main content and the sub content by the user identified by the medium ID and the user ID.

Thereby, it is possible to meet the request of the content provider for limiting the number of aggregations of contents recorded on a plurality of recording mediums onto a single recording medium.

(5) Furthermore, as shown inFIG. 32, the aggregation judgment information may be recorded on theoptical disc31 for distribution. To be more specific, theaggregation apparatus36 may read the aggregation judgment information from theoptical disc31, instead of sending the medium ID to theserver34 and receiving the aggregation judgment information from theserver34.

Thereby, the same effect as that in the third embodiment can be obtained even if theaggregation apparatus36 does not communicate with theserver34.

Note that the aggregation judgment information may be recorded on thememory card32, together with a sub content obtained from theserver34 via the subcontent obtainment apparatus35.

In addition, in a case where theaggregation apparatus36 records a predetermined number of user's aggregations of a main content and a sub content on theoptical disc31 or thememory card32, theaggregation apparatus36 may rewrite the aggregation judgment information recorded on theoptical disc31 so that no more aggregation cannot be done when the number of actual aggregations has reached the predetermined number of aggregations.

Thereby, it is possible to meet the request of the content provider for limiting the number of aggregations of contents onto a single recording medium even if theaggregation apparatus36 does not communicate with theserver34.

(6) The medium ID recorded on theoptical disc31 may be any other ID as long as it can identify what the content recorded on theoptical disc31 is.

For example, it may be a content name, a content ID or the like.

(7) It is possible that theserver34, sends, to theaggregation apparatus36, the information that cannot be created by any other devices than theserver34, as well as the aggregation judgment information, and theaggregation apparatus36 judges whether the aggregation judgment information is authentic or not using that information and aggregates contents when it is authentic. For example, when sending the aggregation judgment information to theaggregation apparatus36, theserver34 attaches a digital signature to it. To be more specific, theserver34 creates a digital signature using its own signature key, and attaches the digital signature and a public key for signature verification (or a certificate for the public key for signature verification) to the aggregation judgment information. Theaggregation apparatus36 verifies the aggregation judgment information using the signature verification key before aggregation, and then aggregates contents based on the aggregation judgment information if it is authentic as a result of the verification.

When permitting the aggregation, theserver34 creates a digital signature using its own signature key, and sends the digital signature and a public key for signature verification (or a certificate for the public key for signature verification) to theaggregation apparatus36. Theaggregation apparatus36 may aggregate contents by considering that the aggregation is permitted if the digital signature is authentic as a result of the verification using the signature verification key.

Fourth Embodiment

Next, anaggregation system4 in the fourth embodiment of the present invention will be explained below with reference toFIG. 33 toFIG. 38.

When an aggregation apparatus aggregates contents recorded on a plurality of recording mediums and records them onto another recording medium, thisaggregation system4 limits the use of the contents recorded on another recording medium.

Overview ofAggregation System4

First, the overview of theaggregation system4 in the fourth embodiment will be provided with reference toFIG. 33.FIG. 33 is a block diagram showing the configuration of theaggregation system4 in the fourth embodiment.

InFIG. 33, a content such as a movie is recorded, as a main content, on anoptical disc41, a sub content such as audio data to be used in association with the main content recorded on theoptical disc41 can be recorded on amemory card42, and aportable medium43 is a portable medium such as a DVD-RAM on which information can be recorded. The portable medium43 may be a removable HDD, or may be replaced with a recording medium such as a nonremovable HDD.

A content provider distributes a main content to a user via a distribution means such as a sale of the main content recorded on theoptical discs41, and distributes a sub content to be used in association with the main content to the user from aserver44 via theInternet48.

On the other hand, the user obtains the sub content from theserver44 via theInternet48 using a subcontent obtainment apparatus45, and records it on thememory card42. Then, using areproduction apparatus47, the user reproduces the main content recorded on theoptical disc41 by associating it with the sub content recorded on thememory card42, and views it.

In order to enhance convenience of portability, the user can record, on theportable medium43, the main content recorded on theoptical disc41 and the sub content recorded on thememory card42, using theaggregation apparatus46. The user can also reproduce and view the main content and the sub content which are recorded on the portable medium43 by associating them with each other, using thereproduction apparatus47. Note that the use of the main content recorded on theportable medium43 is limited. For example, the number of uses of the main content is limited, or the user is billed for his/her use thereof.

Thisaggregation system4 is a system for protecting copyrights of contents by putting limitations on user's use of another recording medium on which the contents recorded on a plurality of recording mediums are aggregated and recorded.

The overview of theaggregation system4 in the fourth embodiment has been provided, and the detailed explanation of theaggregation system4 will follow.

Configuration ofAggregation System4

As shown inFIG. 33, theaggregation system4 includes theoptical disc41, thememory card42, theportable medium43, theserver44, the subcontent obtainment apparatus45, theaggregation apparatus46 and thereproduction apparatus47, and theserver44 and the subcontent obtainment apparatus45 are connected with each other via theInternet48.

Structure ofOptical Disc41

Theoptical disc41 is a portable medium such as a DVD-RAM on which information can be recorded. A main content is recorded on theoptical disc41 here.

Structure ofMemory Card42

Thememory card42 is a recording medium such as an SD card on which information can be recorded. On thememory card42, a sub content to be used in association with the main content is recorded by the subcontent obtainment apparatus45.

Structure ofPortable Medium43

Theportable medium43 is a portable medium such as a DVD-RAM on which information can be recorded. The main content recorded on theoptical disc41 and the sub content recorded on thememory card42 are aggregated and recorded on the portable medium43 by theaggregation apparatus46. Note that, as mentioned above, the portable medium43 may be a removable HDD, or may be replaced with a recording medium such as a nonremovable HDD. In short, the portable medium43 or the recording medium that replaces the portable medium43 must be a recording medium on which aggregated main content and sub content are recorded.

As shown inFIG. 34, the number of uses of theportable medium43 is recorded on the portable medium43 on every use thereof.

Note that the default value of the number of uses of the portable medium43 shall be 0.

Structure ofServer44

Theserver44 holds the sub content to be used in association with the main content recorded on theoptical disc41, and provides the subcontent obtainment apparatus45 with the sub content.

Structure of SubContent Obtainment Apparatus45

The subcontent obtainment apparatus45 obtains the sub content from theserver44 via theInternet48, and records it on thememory card42.

Structure ofAggregation Apparatus46

FIG. 35 shows the structure of theaggregation apparatus46. As shown inFIG. 35, theaggregation apparatus46 includes afirst access unit461, asecond access unit462, acontrol unit463, athird access unit464, aninput unit465, and adisplay unit466.

(1)First Access Unit461

Thefirst access unit461 reads the main content from theoptical disc41 according to the instruction of thecontrol unit463.

(2)Second Access Unit462

Thesecond access unit462 reads the sub content from thememory card42 according to the instruction of thecontrol unit463.

(3)Control Unit463

Thecontrol unit463 reads the main content from theoptical disc41 via thefirst access unit461, and reads the sub content from thememory card42 via thesecond access unit462.

Then, thecontrol unit463 writes the main content and the sub content on theportable medium43 via thethird access unit464.

(4)Third Access Unit464

Thethird access unit464 writes the main content and the sub content on the portable medium43 according to the instruction of thecontrol unit463.

(5)Input Unit465

Theinput unit465 accepts an input of an aggregation instruction from a user.

Then, upon receipt of the input of the aggregation instruction from the user, theinput unit465 causes thecontrol unit463 to operate.

(6)Display Unit466

After thecontrol unit463 completes writing of the main content and the sub content onto theportable medium43, thedisplay unit466 notifies the user of the end of the processing by displaying it.

Structure ofReproduction Apparatus47

FIG. 36 shows the structure of thereproduction apparatus47. As shown inFIG. 36, thereproduction apparatus47 includes afirst access unit4701, asecond access unit4702, athird access unit4703, acontrol unit4704, areproduction unit4705, aninput unit4706 and a predeterminednumber storage unit4707.

(1)First Access Unit4701

Thefirst access unit4701 reads the main content from theoptical disc41 according to the instruction of thecontrol unit4704.

(2)Second Access Unit4702

Thesecond access unit4702 reads the sub content from thememory card42 according to the instruction of thecontrol unit4704.

(3)Third Access Unit4703

Thethird access unit4703 reads the main content, the sub content and the number of uses of the portable medium43 from theportable medium43, according to the instruction of thecontrol unit4704.

Thethird access unit4703 also writes the number of uses of the portable medium43 on theportable medium43, according to the instruction of thecontrol unit4704.

Thethird access unit4703 further deletes the main content recorded on theportable medium43, according to the instruction of thecontrol unit4704.

(4)Control Unit4704

Thecontrol unit4704 performs either the following processing (i) or (ii) according to the instruction of theinput unit4706.

(i) To cause thereproduction unit4705 to reproduce the main content recorded on theoptical disc41 and the sub content recorded on thememory card42 by associating them with each other.

Thecontrol unit4704 reads the main content from theoptical disc41 via thefirst access unit4701, and reads the sub content from thememory card42 via thesecond access unit4702. Then, thecontrol unit4704 causes thereproduction unit4705 to reproduce the main content and the sub content by associating them with each other and output them to the outside.

(ii) To cause thereproduction unit4705 to reproduce the main content and the sub content which are recorded on the portable medium43 by associating them with each other.

Thecontrol unit4704 reads the main content, the sub content and the number of uses of the portable medium43 from theportable medium43 via thethird access unit4703.

Then, thecontrol unit4704 increments the number of uses of the portable medium43 by one, and writes the incremented number of uses of the portable medium43 on theportable medium43.

Then, thecontrol unit4704 causes thereproduction unit4705 to reproduce the main content and the sub content by associating them with each other and output them to the outside.

When the number of uses of theportable medium43 has reached a predetermined number of uses, for example, three times, thecontrol unit4704 deletes the main content and the sub content which are recorded on theportable medium43, via thethird access unit4703. Note that the predetermined number of uses, that is, the upper limit of the number of times up to which the user can use theportable medium43, is stored in the predeterminednumber storage unit4707.

(5)Reproduction Unit4705

Thereproduction unit4705 reproduces the main content and the sub content by associating them with each other under the control of thecontrol unit4704, and outputs the reproduced data to amonitor471 and aspeaker472 which are connected to thereproduction unit4705. Themonitor471 and thespeaker472 output the data reproduced by thereproduction unit4705 to the outside.

(6)Input Unit4706

Theinput unit4706 accepts an instruction to reproduce theoptical disc41 or an instruction to reproduce the portable medium43 from the user.

Upon receipt of the instruction to reproduce theoptical disc41, theinput unit4706 causes thecontrol unit4704 to operate so that the main content recorded on theoptical disc41 and the sub content recorded on thememory card42 are reproduced in association with each other.

On the other hand, upon receipt of the instruction to reproduce theportable medium43, theinput unit4706 causes thecontrol unit4704 to operate so that the main content and the sub content which are recorded on the portable medium43 are reproduced in association with each other.

(7) PredeterminedNumber Storage Unit4707

The predeterminednumber storage unit4707 stores the predetermined number of uses, that is, the upper limit of the number of times up to which the user can use theportable medium43.

It is assumed in the fourth embodiment that the predetermined number of uses is stored in the predeterminednumber storage unit4707, but it may be recorded on a recording medium such as a memory card. In short, the predetermined number of uses can be used by thecontrol unit4707. Therefore, the predetermined number of uses may be obtained by thecontrol unit4707 via theInternet48, or may be stored in thecontrol unit4704.

Operation ofAggregation System4

The configuration of theaggregation system4 has been explained, and the detailed explanation of the operations of theaggregation apparatus46 and thereproduction apparatus47, as the operation of theaggregation system4, will follow.

Operation ofAggregation Apparatus46

The operation of theaggregation apparatus46 will be explained with reference to the flowchart as shown inFIG. 37.

When theinput unit465 receives the input of the aggregation instruction from the user, theaggregation apparatus46 performs the following processing.

First, thecontrol unit463 reads the main content from theoptical disc41 via thefirst access unit461, and reads the sub content from thememory card42 via the second access unit462 (Step S401).

Then, thecontrol unit463 writes the main content and the sub content on theportable medium43 via the third access unit464 (Step S402).

Next, thedisplay unit466 displays that writing of the main content and the sub content onto theportable medium43 has been completed (Step S403). Then, the operation of theaggregation apparatus46 ends.

Operation ofReproduction Apparatus47

The operation of thereproduction apparatus47 will be explained with reference to the flowchart as shown inFIG. 38.

When theinput unit4706 receives the instruction to reproduce theoptical disc41 or the instruction to reproduce the portable medium43 from the user, thereproduction apparatus47 performs the following operation.

First, theinput unit4706 checks whether the received reproduction instruction is the instruction to reproduce theoptical disc41 or the instruction to reproduce the portable medium43 (Step S451). The processing goes to Step S452 in the case of the instruction to reproduce theoptical disc41, whereas the processing goes to Step S454 in the case of the instruction to reproduce theportable medium43.

To be more specific, in a case where the reproduction instruction received by theinput unit4706 is the instruction to reproduce the optical disc41 (No in Step S451), thecontrol unit4704 reads the main content from theoptical disc41 via thefirst access unit4701, and reads the sub content from thememory card42 via the second access unit4702 (Step5452).

Next, thecontrol unit4704 causes thereproduction unit4705 to reproduce the main content and the sub content by associating them with each other (Step S453). The reproduced data is outputted to the outside via themonitor471 and thespeaker472. Thereby, the operation of thereproduction apparatus47 ends.

On the other hand, in a case where the reproduction instruction received by theinput unit4706 is the instruction to reproduce the portable medium43 (Yes in Step S451), thecontrol unit4704 reads the main content, the sub content and the number of uses of the portable medium43 from theportable medium43 via the third access unit4703 (Step S454). Then, thecontrol unit4704 increments the number of uses of the portable medium43 by one, and writes the incremented number of uses of the portable medium43 on theportable medium43 via the third access unit4703 (Step S455).

Then, thecontrol unit4704 reads, from the predeterminednumber storage unit4707, the predetermined number of uses that is the maximum number of times to which the user can use the portable medium43 (Step S456).

Thecontrol unit4704 checks whether the number of uses of theportable medium43 has reached the predetermined number or not (Step S457). When it has reached the predetermined number of uses (Yes in Step S457), thecontrol unit4704 deletes the main content and the sub content which are recorded on theportable medium43, via the third access unit4703 (Step S458). Thereby, the operation of thereproduction apparatus47 ends.

On the other hand, when the number of uses of theportable medium43 has not yet reached the predetermined number (No in Step S457), thecontrol unit4704 causes thereproduction unit4705 to reproduce the main content and the sub content by associating them with each other (Step S459). The reproduced data is outputted to the outside via themonitor471 and thespeaker472. Thereby, the operation of thereproduction apparatus47 ends.

Verification of Operation ofAggregation System4

The overall operation of theaggregation system4 in the fourth embodiment will be summarized below.

First, theaggregation apparatus46 reads the main content from theoptical disc41, reads the sub content from thememory card42, and records the main content and the sub content onto theportable medium43.

When reproducing the main content recorded on theoptical disc41 and the sub content recorded on thememory card42, thereproduction apparatus47 reads the main content from theoptical disc41, reads the sub content from thememory card42, and causes thereproduction unit4705 to reproduce the main content and the sub content by associating them with each other and output the reproduced data to the outside.

On the other hand, when reproducing the main content and the sub content which are recorded on theportable medium43, thereproduction apparatus47 reads the main content and the sub content from theportable medium43, and causes thereproduction unit4705 to reproduce the main content and the sub content by associating them with each other and output the reproduced data to the outside. Note that thereproduction apparatus47 deletes the main content and the sub content which are recorded on the portable medium43 when theportable medium43 has been used the predetermined number of times.

As a result, the user can reproduce the main content recorded on theoptical disc41 and the sub content recorded on thememory card42 by associating them with each other. In addition, for the sake of enhancing convenience of portability, the user can reproduce the main content and the sub content which are recorded on the portable medium43 by associating them with each other, by aggregating the main content recorded on theoptical disc41 and the sub content recorded on thememory card42 and recording them onto theportable medium43.

Effect Obtained in Fourth Embodiment

In the fourth embodiment, the number of uses of theportable medium43 is recorded on theportable medium43. Thereproduction apparatus47 updates the number of uses to be recorded on the portable medium43 every time this portable medium43 is used. When the number of uses has reached the predetermined number, the main content and the sub content which are recorded on the portable medium43 are deleted from theportable medium43.

Thereby, the contents which are aggregated and recorded on another recording medium can only be reproduced within the predetermined number of uses. As a result, differently from the conventional techniques, theaggregation system4 protects the copyrights of the contents by putting limitations on the uses of the contents which are recorded onto another recording medium.

Modifications

Although the fourth embodiment has been fully described by way of one example of the embodiments of the present invention, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein. The embodiment of the present invention also includes the following modifications:

(1) In the present embodiment, thereproduction apparatus47 increments the number of uses to be recorded on the portable medium43 by one every time theportable medium43 is used, and deletes the main content and the sub content when the number of uses has reached a predetermined number. However, it is also possible to record the predetermined number of uses on the portable medium43 when the main content and the sub content are aggregated and recorded onto theportable medium43, decrement the predetermined number recorded on the portable medium43 by one every time theportable medium43 is used, and delete the main content and the sub content when the predetermined number has reached 0.

(2) It is also possible that theportable medium43 includes a clock for measuring the time for which theportable medium43 has been used, a predetermined time is recorded on theportable medium43, and thereproduction apparatus47 deletes the main content and the sub content when the used time has reached the predetermined time. Or, the predetermined time may have already been recorded on the portable medium43 when the main content and the sub content are aggregated and recorded onto theportable medium43. In that case, thereproduction apparatus47 may subtract the used time from the remaining reproduction time recorded and updated on the portable medium43 every time theportable medium43 is used, and delete the main content and the sub content when the recorded remaining time has reached 0.

(3) When using theportable medium43, thereproduction apparatus47 may increment the number of uses to be recorded on the portable medium43 by one when the used time exceeds the predetermined minimum used time.

Or, assuming that the total used time is recorded on theportable medium43, thereproduction apparatus47 may delete the main content and the sub content when the total used time has reached a predetermined time.

Furthermore, using these conditions in combinations, thereproduction apparatus47 may delete the main content and the sub content when all the conditions are satisfied.

(4) Note that the number of uses to be recorded on the portable medium43 may be encrypted for protection against tampering, or all the information to be recorded on the portable medium43 may be encrypted.

In addition, the portable medium43 may include a CPU for mutual authentication with thereproduction apparatus47. When thereproduction apparatus47 is authenticated by the CPU, it is permitted to access theportable medium43 for reading and writing. By doing so, there is no exchange of data with an unauthenticated reproduction apparatus which may tamper the data, so protection against tampering can be achieved.

(5) The predetermined number of uses indicating the upper limit of the number of times up to which the portable medium43 can be used does not need to be a fixed value, but may be recorded previously on theoptical disc41 for each content and be recorded on the portable medium43 when contents are aggregated. In addition, the predetermined number of uses may be obtained from theserver44 via theInternet48.

(6) Furthermore, the main content recorded on theoptical disc41 may be encrypted. A decryption key for decrypting the encrypted main content and the medium ID may also be recorded on theoptical disc41. Under the circumstances, when the decryption key and the medium ID are managed by theserver44 and thereproduction apparatus47 can access theserver44 via theInternet48, theaggregation apparatus46 may record only the encrypted main content and the medium ID on theportable medium43, not recording the decryption key. In this case, when reproducing theportable medium43, thereproduction apparatus47 sends the medium ID to theserver44 to obtain the decryption key that corresponds to the medium ID from theserver44, decrypts the encrypted main content recorded on the portable medium43 using the obtained decryption key, and then reproduces the main content.

Note that the medium ID to be recorded on theoptical disc41 may be any other ID as long as it can identify what the content recorded on theoptical disc41 is. For example, it may be a content name, a content ID or the like.

At that time, billing processing may be performed for user's content use.

Thereby, it is possible to meet the request of the content provider for permitting only the user who accepts the billing from the content provider to use the contents aggregated and recorded onto a single recording medium from a plurality of recording mediums.

Other Modifications

Although the first through fourth embodiments have been fully described by way of examples of the embodiments of the present invention, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein. The embodiments of the present invention also include the following modifications:

(1) Assuming that there are a plurality of optical discs11 (oroptical discs21,31 or41) (which are hereinafter referred to as optical discs), main contents may be recorded on the plurality of optical discs. Or, assuming that there are a plurality of portable mediums13 (orportable mediums23,33 or43) (which are hereinafter referred to as portable mediums), main contents and sub contents may be aggregated and recorded on the plurality of portable mediums.

(2) In the above first through fourth embodiments, the sub content obtainment apparatus15 (or the subcontent obtainment apparatus25,35 or45) (which is hereinafter referred to as a sub content obtainment apparatus) records a sub content on the memory card12 (or thememory card22,32 or42) (which is hereinafter referred to as a memory card), and the aggregation apparatus16 (or theaggregation apparatus26,36 or46) (which is hereinafter referred to as an aggregation apparatus) or the reproduction apparatus17 (or thereproduction apparatus27,37 or47) (which is hereinafter referred to as a reproduction apparatus) reads the sub content via the memory card. However, the aggregation apparatus or the reproduction apparatus itself may obtain the sub content from the server14 (or theserver24,34 or44) via the Internet18 (or theInternet28,38 or48).

(3) When the sub content obtainment apparatus15 (or the subcontent obtainment apparatus25,35 or45) (which is hereinafter referred to as a sub content obtainment apparatus) obtains a sub content from the server14 (or theserver24,34 or44) (which is hereinafter referred to as a server), the server and the sub content obtainment apparatus may authenticate each other and share a key so that the sub content is obtained securely.

To be more specific, it is assumed, for example, that the server and the sub content obtainment apparatus have the public key certificates. When the sub content obtainment apparatus obtains a sub content from the server, it sends its own public key certificate to the server and receives the public key certificate of the server. Then, the sub content obtainment apparatus and the server verify the public key certificates each other, and after the verification, share a temporary key CK under the Diffie-Hellman key exchange protocol. Then, the server encrypts the sub content using the temporary key CK and sends it to the sub content obtainment apparatus. The sub content obtainment apparatus decrypts the sub content encrypted using the temporary key so as to obtain the original sub content.

As for the public key certificate, “Digital Shomei to Angou Gijutsu” (in Japanese) written by Shin'ichiro Yamada (Pearson Education Japan, p. 159-p. 214, 1997) describes it in detail, and as for the Diffie-Hellman key exchange, “Gendai Angou” (in Japanese) written by Tatsuaki Okamoto and Hirosuke Yamamoto (Series/Jouhou Kagaku no Suugaku, Sangyo Tosho, 1997) describes it in detail, so the detailed explanation thereof is not repeated here.

As a result, since the sub content is obtained securely, the copyrights of the contents are protected more securely.

(4) In the above embodiments, when the aggregation apparatus16 (or theaggregation apparatus26,36 or46) (which is hereinafter referred to as an aggregation apparatus) aggregates the main content and the sub content and records them onto the portable medium13 (or theportable medium23,33 or43) (which is hereinafter referred to as a portable medium), it writes the main content and the sub content onto the portable medium. However, any other method may be used as long as it enables the reproduction apparatus17 (or thereproduction apparatus27,37 or47) to reproduce the main content and the sub content by associating them with each other.

For example, as described above, in a case where the main content and the sub content are reproduced in association with each other by replacing the audio data of the main content with the audio data of the sub content for reproduction, the aggregation apparatus may record only the video data of the main content and the audio data of the sub content onto the portable medium.

(5) In the above embodiment, the reproduction apparatus17 (or thereproduction apparatus27,37 or47) (which is hereinafter referred to as a reproduction apparatus) reproduces the main content and the sub content by associating them with each other by replacing the audio data of the main content with the audio data of the sub content. However, any other method may be used as long as it enables the reproduction apparatus to reproduce the main content into which the information of the sub content is incorporated.

For example, in a case where the main content is digital data composed of audio and video and the sub content is digital data composed of subtitles, the reproduction apparatus may add the subtitles of the sub content to the video data of the main content for reproduction.

(6) Furthermore, the aggregation apparatus16 (or theaggregation apparatus26,36 or46) may further aggregate contents aggregated and recorded onto the portable medium13 (or theportable medium23,33 or43) and a sub content recorded on another memory card12zand record them onto still another portable medium13z.

To be more specific, when aggregating and recording the contents onto theportable medium13, theaggregation apparatus16 also records the reproduction judgment information on theportable medium13 and determines the default value thereof to be 1. Then, thefirst access unit161 reads the aggregated contents from theportable medium13, thesecond access unit162 reads the sub content from the memory card12z, and thethird access unit164 further aggregate the aggregated contents and the sub content and writes them onto the portable medium13z, and after the aggregation, rewrites the reproduction judgment information on theportable medium13. By doing so, it is possible to further aggregate the contents aggregated and recorded onto theportable medium13 and the sub content recorded on the memory card12zand record them onto the portable medium13z. Since the portable medium13 cannot be reproduced any more, the copyrights of the contents are protected even if they are further aggregated, as is the case with the first embodiment.

In addition, for example, thefirst access unit261 reads the aggregated contents from theportable medium23, thesecond access unit262 reads the sub content from the memory card12z, and thethird access unit264 further aggregates the aggregated contents and the sub content and writes them onto the portable medium13z. By doing so, it is possible to further aggregate the contents aggregated and recorded onto theportable medium23 and the sub content recorded on the memory card12zand record them onto the portable medium13z. Since the decryptionkey storage medium211 is required for the reproduction of the portable medium23 or the portable medium13z, the copyrights of the contents are protected even if they are further aggregated as mentioned above, as is the case with the second embodiment.

As another example, when aggregating contents on theportable medium33, theaggregation apparatus36 records the medium ID read from theoptical disc31 on theportable medium33, the first access unit reads the aggregated contents from theportable medium33, thesecond access unit362 reads the sub content from the memory card12z, and the third access unit further aggregates the aggregated contents and the sub content and writes them onto the portable medium13z. By doing so, it is possible to further aggregate the contents aggregated and recorded onto theportable medium33 and the sub content recorded on the memory card12zand record them onto the portable medium13z. The medium ID read from theoptical disc31 is recorded on theportable medium33, and theaggregation apparatus36 determines whether or not to aggregate and record the contents onto the portable medium13zbased on this medium ID and the aggregation judgment information, so the copyrights of the contents are protected even if they are further aggregated as mentioned above, as is the case with the third embodiment.

As still another example, thefirst access unit461 reads the aggregated contents and the number of uses from theportable medium43, thesecond access unit462 reads the sub content from the memory card12z, and thethird access unit464 further aggregates the aggregated contents and the sub content and writes them, together with the number of uses, onto the portable medium13z, and rewrites the number of uses on the portable medium43 to 0. By doing so, it is possible to further aggregate the contents aggregated and recorded onto theportable medium43 and the sub content recorded on the memory card12zand record them onto the portable medium13z. And the number of uses recorded on theportable medium43 is inherited as it is to the number of uses recorded on the portable medium13z, so the copyrights of the contents are protected even if they are further aggregated as mentioned above, as is the case with the fourth embodiment.

As a result, it is possible to further aggregate the contents which have been aggregated once on the portable medium13 (or theportable medium23,33 or43) and the sub content and to record them onto another medium, while protecting the copyrights of the contents.

(7) The present invention may be any of the methods as described above, a computer program for causing a computer to realize any of these methods, or a digital signal consisting of the computer program.

The present invention may be a computer readable recording medium, such as a semiconductor memory, a hard disk drive, a CD-ROM, a DVD-ROM and a DVD-RAM, on which the above-mentioned computer program or the digital signal is recorded.

(8) Each of the above-mentioned embodiments and modifications may be combined.

As described above, the present invention provides the aggregation system which has not been realized by the conventional technology, and thus is of great value.

The aggregation system of the present invention has the effect of aggregating contents which are recorded on a plurality of recording mediums and recording them onto another recording medium while protecting the copyrights of the contents, or reproducing the aggregated contents while protecting the copyrights of the contents. Therefore, the present invention is of value as an aggregation system or the like for aggregating contents which are recorded on a plurality of recording mediums and recording them onto a single recording medium.

Claims (26)

1. An aggregation system comprising an aggregation apparatus, a first reproduction apparatus and a second reproduction apparatus,

wherein said aggregation apparatus includes:

a first obtainment unit operable to obtain a main content including video data and audio data from a first recording medium;

a second obtainment unit operable to obtain a sub content including either audio data or subtitle data; and

a recording unit operable to aggregate the main content and the sub content and record the aggregated contents onto a second recording medium,

said first reproduction apparatus includes:

a third obtainment unit operable to obtain the main content from the first recording medium;

a fourth obtainment unit operable to obtain reproduction control information for controlling reproduction of the main content; and

a reproduction unit operable to reproduce the main content recorded on the first recording medium and the sub content, based on the reproduction control information, so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced, and

said second reproduction apparatus reproduces the main content and the sub content which are recorded on the second recording medium so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced.

2. The aggregation system according toclaim 1,

wherein the reproduction control information indicates whether or not reproduction of the main content is permitted, and is recorded on the first recording medium,

said aggregation apparatus further includes:

a fifth obtainment unit operable to obtain the reproduction control information from the first recording medium;

a first judgment unit operable to judge whether or not the reproduction control information obtained by the fifth obtainment unit is information indicating that reproduction of the main content is permitted; and

a changing unit operable to change the reproduction control information recorded on the first recording medium so that the reproduction control information indicates that reproduction of the main content is not permitted, in the case where the main content and the sub content are recorded onto the second recording medium by the recording unit,

the first reproduction apparatus includes a second judgment unit operable to judge whether or not the reproduction control information obtained by the fourth obtainment unit is the information indicating that reproduction of the main content is permitted,

the recording unit aggregates the main content obtained by the first obtainment unit and the sub content obtained by the second obtainment unit and records the aggregated contents onto the second recording medium, when the first judgment unit judges that the reproduction control information is the information indicating that reproduction of the main content is permitted,

the fourth obtainment unit obtains the reproduction control information from the first recording medium, and

the reproduction unit reproduces the main content recorded on the first recording medium, when the second judgment unit judges that the reproduction control information is the information indicating that reproduction of the main content is permitted.

3. The aggregation system according toclaim 2,

wherein said first reproduction apparatus and said second reproduction apparatus are identical.

4. The aggregation system according toclaim 2,

wherein a format of the main content recorded on the first recording medium is same as a format of the main content recorded on the second recording medium.

5. The aggregation system according toclaim 2,

wherein the reproduction control information is index information which is required for reading the main content.

6. The aggregation system according toclaim 2,

wherein the main content is encrypted, and

the reproduction control information is a decryption key for decrypting the encrypted main content.

7. The aggregation system according toclaim 2,

wherein a special area which can be physically destroyed is provided in the first recording medium,

the reproduction control information is recorded in the special area, and

the changing unit destroys the special area to prevent reproduction of the main content.

8. An aggregation apparatus for (i) aggregating a main content including video data and audio data recorded on a first recording medium and a sub content including either audio data or subtitle data and (ii) recording the aggregated contents onto a second recording medium, the aggregation apparatus comprising:

a first obtainment unit operable to obtain the main content from the first recording medium recording reproduction control information, on the first recording medium, indicating whether or not reproduction of the main content and the sub content is permitted, the main content and the sub content being reproduced so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced;

a second obtainment unit operable to obtain the sub content;

a third obtainment unit operable to obtain the reproduction control information from the first recording medium;

a judgment unit operable to judge whether or not the reproduction control information is information indicating that reproduction of the main content and the sub content is permitted;

a recording unit operable to aggregate the main content and the sub content and record the aggregated contents onto the second recording medium, when said judgment unit judges that the reproduction control information is the information indicating that reproduction of the main content and the sub content is permitted; and

a changing unit operable to change the reproduction control information recorded on the first recording medium so that said reproduction control information indicates that reproduction of the main content and the sub content is not permitted, in the case where the main content and the sub content are recorded onto the second recording medium by said recording unit.

9. A reproduction apparatus for reproducing (i) a main content including video data and audio data recorded on a recording medium, and (ii) sub content including either audio data or subtitle data, the reproduction apparatus comprising:

a first obtainment unit operable to obtain (i) the main content from the recording medium, and (ii) the sub content, the sub content being obtained for reproduction, and the recording medium recording reproduction control information, on the recording medium, indicating whether or not reproduction of the main content and the sub content is permitted, the main content and the sub content being reproduced so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced;

a second obtainment unit operable to obtain the reproduction control information from the recording medium;

a judgment unit operable to judge whether or not the reproduction control information is information indicating that reproduction of the main content and the sub content is permitted; and

a reproduction unit operable to reproduce the main content recorded on the recording medium and the sub content so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced, when the judgment unit judges that the reproduction control information is the information indicating that reproduction of the main content and the sub content is permitted.

10. An aggregation method for (i) aggregating a main content including video data and audio data recorded on a first recording medium and a sub content including either audio data or subtitle data and (ii) recording the aggregated contents onto a second recording medium, the aggregation method comprising:

a first obtainment step of obtaining the main content from the first recording medium recording reproduction control information, on the first recording medium, indicating whether or not reproduction of the main content and the sub content is permitted, the main content and the sub content being reproduced so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced;

a second obtainment step of obtaining the sub content;

a third obtainment step of obtaining the reproduction control information from the first recording medium;

a judgment step of judging whether or not the reproduction control information is information indicating that reproduction of the main content and the sub content is permitted;

a recording step of aggregating the main content and the sub content and recording the aggregated contents onto the second recording medium, when it is judged in the judgment step that the reproduction control information is the information indicating that reproduction of the main content and the sub content is permitted; and

a changing step of changing the reproduction control information recorded on the first recording medium so that said reproduction control information indicates that reproduction of the main content and the sub content is not permitted, in the case where the main content and the sub content are recorded onto the second recording medium in the recording step.

11. A reproduction method for reproducing (i) a main content including video data and audio data recorded on a recording medium and (ii) a sub content including either audio or data subtitle data, the reproduction method comprising:

a first obtainment step of obtaining (i) the main content from the recording medium, and (ii) the sub content, the sub content being obtained for reproduction and the recording medium recording reproduction control information, on the recording medium, indicating whether or not reproduction of the main content and the sub content is permitted, the main content and the sub content being reproduced so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced;

a second obtainment step of obtaining the reproduction control information from the recording medium;

a judgment step of judging whether or not the reproduction control information is information indicating that reproduction of the main content and sub content is permitted; and

a reproduction step of reproducing the main content recorded on the recording medium and the sub content, so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced, when it is judged in the judgment step that the reproduction control information is the information indicating that reproduction of the main content and the sub content is permitted.

12. A program stored on a computer-readable recording medium for (i) aggregating a main content including video data and audio data recorded on a first recording medium and a sub content including either audio data or subtitle data and (ii) recording the aggregated contents onto a second recording medium, the program causing a computer to execute:

a first obtainment step of obtaining the main content from the first recording medium recording reproduction control information, on the first recording medium, indicating whether or not reproduction of the main content and the sub content is permitted, the main content and the sub content being reproduced so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced;

a second obtainment step of obtaining the sub content;

a third obtainment step of obtaining the reproduction control information from the first recording medium;

a judgment step of judging whether or not the reproduction control information is information indicating that reproduction of the main content and the sub content is permitted;

a recording step of aggregating the main content and the sub content and recording the aggregated contents onto the second recording medium, when it is judged in the judgment step that the reproduction control information is the information indicating that reproduction of the main content and the sub content is permitted; and

a changing step of changing the reproduction control information recorded on the first recording medium so that said reproduction control information indicates that reproduction of the main content and the sub content is not permitted, in the case where the main content and the sub content are recorded onto the second recording medium in the recording step.

13. A program stored on a computer-readable recording medium for reproducing (i) a main content including video data and audio data recorded on a recording medium, and (ii) a sub content including either audio data or subtitle data, the program causing a computer to execute:

a first obtainment step of obtaining (i) the main content from the recording medium, and (ii) the sub content, the sub content being obtained for reproduction and the recording medium recording reproduction control information, on the recording medium, indicating whether or not reproduction of the main content and the sub content is permitted, the main content and the sub content being reproduced so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced;

a second obtainment step of obtaining the reproduction control information from the recording medium;

a judgment step of judging whether or not the reproduction control information is information indicating that reproduction of the main content and the sub content is permitted; and

a reproduction step of reproducing the main content recorded on the recording medium and the sub content, so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced, when it is judged in the judgment step that the reproduction control information is the information indicating that reproduction of the main content and the sub content is permitted.

14. An aggregation system comprising an aggregation apparatus and a reproduction apparatus, wherein said aggregation apparatus includes:

a first obtainment unit operable to obtain a main content including video data and audio data;

a second obtainment unit operable to obtain a sub content including either audio data or subtitle data;

a third obtainment unit operable to obtain aggregation judgment information indicating whether or not aggregation of the main content and the sub content and recording of the aggregated contents onto a recording medium are permitted;

a judgment unit operable to judge whether or not the aggregation judgment information is information indicating that aggregation of the main content and the sub content and recording of the aggregated contents onto the recording medium are permitted; and

a recording unit operable to aggregate the main content and the sub content and record the aggregated contents onto the recording medium, when the judgment unit judges that the aggregation judgment information is the information indicating that aggregation and recording onto the recoding medium are permitted, and

said reproduction apparatus reproduces the main content and the sub content which are recorded on the recording medium so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced.

15. An aggregation apparatus for (i) aggregating a main content including video data and audio data and a sub content including either audio data or subtitle data and (ii) recording the aggregated contents onto a first recording medium, comprising:

a first obtainment unit operable to obtain the main content;

a second obtainment unit operable to obtain the sub content;

a third obtainment unit operable to obtain aggregation judgment information indicating whether or not aggregation of the main content and the sub content and recording of the aggregated contents onto the first recording medium are permitted, the aggregation being executed so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced;

a judgment unit operable to judge whether or not the aggregation judgment information is information indicating that aggregation of the main content and the sub content and recording of the aggregated contents onto the first recording medium are permitted; and

a recording unit operable to aggregate the main content and the sub content and record the aggregated contents onto the first recording medium, when said judgment unit judges that the aggregation judgment information is the information indicating that aggregation and recording onto the first recording medium are permitted.

16. The aggregation apparatus according toclaim 15, wherein the main content is recorded on a second recording medium, and a predetermined identifier is further recorded on the second recording medium, the aggregation apparatus further comprises:

a fourth obtainment unit operable to obtain the predetermined identifier from the second recording medium; and

a sending unit operable to send the predetermined identifier to a predetermined apparatus for sending the aggregation judgment information based on the predetermined identifier,

said first obtainment unit obtains the main content from the second recording medium, and

said third obtainment unit obtains the aggregation judgment information by receiving said aggregation judgment information from the predetermined apparatus.

17. The aggregation apparatus according toclaim 16, wherein the predetermined identifier is a medium identifier that specifies the second recording medium.

18. The aggregation apparatus according toclaim 16, wherein the predetermined identifier is a content identifier that specifies the main content.

19. The aggregation apparatus according toclaim 15,

wherein the aggregation judgment information is information indicating whether or not aggregation of the main content and the sub content and recording of the aggregated contents onto the first recording medium are permitted, depending on billing for aggregation of the main content and the sub content.

20. The aggregation apparatus according toclaim 15,

wherein the aggregation judgment information is information indicating whether or not aggregation of the main content and the sub content and recording of the aggregated contents onto the first recording medium are permitted, depending on the number of aggregations of the main content and the sub content.

21. The aggregation apparatus according toclaim 15,

wherein the main content and the aggregation judgment information are recorded on a second recording medium,

said first obtainment unit obtains the main content from the second recording medium, and

said third obtainment unit obtains the aggregation judgment information from the second recording medium.

22. An aggregation method for (i) aggregating a main content including video data and audio data and a sub content including either audio data or subtitle data and (ii) recording the aggregated contents onto a recording medium, comprising:

a first obtainment step of obtaining the main content;

a second obtainment step of obtaining the sub content;

a third obtainment step of obtaining aggregation judgment information indicating whether or not aggregation of the main content and the sub content and recording of the aggregated contents onto the recording medium are permitted, the aggregation being executed so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced;

a judgment step of judging whether or not the aggregation judgment information is information indicating that aggregation of the main content and the sub content and recording of the aggregated contents onto the recording medium are permitted; and

a recording step of aggregating the main content and the sub content and recording the aggregated contents onto the recording medium, when it is judged in said judgment step that the aggregation judgment information is the information indicating that aggregation and recording onto the recording medium are permitted.

23. A program stored on a computer-readable recording medium for (i) aggregating a main content including video data and audio data and a sub content including either audio data or subtitle data and (ii) recording the aggregated contents onto a recording medium, the program causing a computer to execute:

a first obtainment step of obtaining the main content;

a second obtainment step of obtaining the sub content;

a third obtainment step of obtaining aggregation judgment information indicating whether or not aggregation of the main content and the sub content and recording of the aggregated contents onto the recording medium are permitted, the aggregation being executed so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced;

a judgment step of judging whether or not the aggregation judgment information is information indicating that aggregation of the main content and the sub content and recording of the aggregated contents onto the recording medium are permitted; and

a recording step of aggregating the main content and the sub content and recording the aggregated contents onto the recording medium, when it is judged in said judgment step that the aggregation judgment information is the information indicating that aggregation and recording onto the recording medium are permitted.

24. An aggregation system comprising an aggregation apparatus, and a reproduction apparatus,

wherein the aggregation apparatus includes:

a first obtainment unit operable to obtain a main content including video data and audio data;

a second obtainment unit operable to obtain a sub content including either audio data or subtitle data; and

a recording unit operable to aggregate the main content and the sub content and record the aggregated contents onto a recording medium, and

the reproduction apparatus includes:

a judgment unit operable to judge whether or not a situation of reproduction of the main content and the sub content satisfies a predetermined condition indicating that reproduction of the main content and the sub content is permitted, the main content and the sub content being reproduced so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced, and

a reproduction unit operable to reproduce the main content and the sub content which are recorded on the recording medium, so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced, when the judgment unit judges that the situation satisfies the predetermined condition.

25. A reproduction method for reproducing a main content and a sub content which are aggregated and recorded onto a recording medium, the encrypted main content including video data and audio data, and the sub content including either audio data or subtitle data, comprising:

a judgment step of judging whether or not a situation of reproduction of the main content and the sub content satisfies a predetermined condition indicating that reproduction of the main content and the sub content is permitted, the main content and sub content being reproduced so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced; and

a reproduction step of reproducing the main content and the sub content which are recorded on the recording medium, so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content or the subtitle data of the sub content to be reproduced, when it is judged in the judgment step that the situation satisfies the predetermined condition.

26. A program stored on a computer-readable recording medium for reproducing a main content and a sub content which are aggregated and recorded onto a recording medium, the encrypted main content including video data and audio data, and the sub content including either audio data or subtitle data, the program causing a computer to execute:

a judgment step of judging whether or not a situation of reproduction of the main content and the sub content satisfies a predetermined condition indicating that reproduction of the main content and the sub content is permitted, the main content and sub content being reproduced so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content to be reproduced; and

a reproduction step of reproducing the main content and the sub content which are recorded on the recording medium, so that the audio data of the main content is replaced with either the audio data of the sub content or the subtitle data of the sub content or the subtitle data of the sub content to be reproduced, when it is judged in the judgment step that the situation satisfies the predetermined condition.

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